{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14703310337664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14703310344512,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14703310354688,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14703310354689,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14703310357248,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14703310359232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14703310359360,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14703310364736,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14703310367488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14703310367680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 9,\n \"timestamp_ns\": 14703310367680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 20}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14703310337664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14703310344512,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14703310354688,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14703310354689,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14703310357248,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14703310359232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14703310359360,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14703310364736,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14703310367488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14703310367680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 9,\n \"timestamp_ns\": 14703310367680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 20}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14703310337664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14703310344512,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14703310354688,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14703310354689,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14703310357248,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14703310359232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14703310359360,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14703310364736,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14703310367488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14703310367680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 9,\n \"timestamp_ns\": 14703310367680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14703310337664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14703310344512,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14703310354688,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14703310354689,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14703310357248,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14703310359232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14703310359360,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14703310364736,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14703310367488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14703310367680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 9,\n \"timestamp_ns\": 14703310367680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14703310337664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14703310344512,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14703310354688,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14703310354689,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14703310357248,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14703310359232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14703310359360,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14703310364736,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14703310367488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14703310367680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 9,\n \"timestamp_ns\": 14703310367680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 10,\n \"timestamp_ns\": 11406248941952,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 11406248951168,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 11406248951552,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 11406248985280,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 11406248989056,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 11406248992832,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 11406248996224,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 11406248997376,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 11406249013440,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 11406249036544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 19,\n \"timestamp_ns\": 11406249036544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 10,\n \"timestamp_ns\": 11406248941952,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 11406248951168,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 11406248951552,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 11406248985280,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 11406248989056,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 11406248992832,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 11406248996224,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 11406248997376,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 11406249013440,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 11406249036544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 19,\n \"timestamp_ns\": 11406249036544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 10,\n \"timestamp_ns\": 11406248941952,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 11406248951168,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 11406248951552,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 11406248985280,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 11406248989056,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 11406248992832,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 11406248996224,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 11406248997376,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 11406249013440,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 11406249036544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 19,\n \"timestamp_ns\": 11406249036544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 10,\n \"timestamp_ns\": 11406248941952,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 11406248951168,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 11406248951552,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 11406248985280,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 11406248989056,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 11406248992832,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 11406248996224,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 11406248997376,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 11406249013440,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 11406249036544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 19,\n \"timestamp_ns\": 11406249036544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 10,\n \"timestamp_ns\": 11406248941952,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 11406248951168,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 11406248951552,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 11406248985280,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 11406248989056,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 11406248992832,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 11406248996224,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 11406248997376,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 11406249013440,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 11406249036544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 19,\n \"timestamp_ns\": 11406249036544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14702295497856,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14702295500608,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14702295504192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14702295504832,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14702295506112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14702295506432,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14702295507072,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 28,\n \"timestamp_ns\": 14702295507328,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 29,\n \"timestamp_ns\": 14702295507392,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14702295508864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 30,\n \"timestamp_ns\": 14702295508864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14702295497856,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14702295500608,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14702295504192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14702295504832,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14702295506112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14702295506432,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14702295507072,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 28,\n \"timestamp_ns\": 14702295507328,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 29,\n \"timestamp_ns\": 14702295507392,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14702295508864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 30,\n \"timestamp_ns\": 14702295508864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14702295497856,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14702295500608,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14702295504192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14702295504832,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14702295506112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14702295506432,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14702295507072,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 28,\n \"timestamp_ns\": 14702295507328,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 29,\n \"timestamp_ns\": 14702295507392,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14702295508864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 30,\n \"timestamp_ns\": 14702295508864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14702295497856,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14702295500608,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14702295504192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14702295504832,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14702295506112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14702295506432,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14702295507072,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 28,\n \"timestamp_ns\": 14702295507328,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 29,\n \"timestamp_ns\": 14702295507392,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14702295508864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 30,\n \"timestamp_ns\": 14702295508864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: one goroutine sends five integers on an unbuffered channel, main receives them all.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\tgo func() {\n\t\tfor i := 0; i < 5; i++ {\n\t\t\tch <- i\n\t\t}\n\t\tclose(ch)\n\t}()\n\tfor v := range ch {\n\t\tfmt.Println(v)\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14702295497856,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14702295500608,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14702295504192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14702295504832,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14702295506112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14702295506432,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14702295507072,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 28,\n \"timestamp_ns\": 14702295507328,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 29,\n \"timestamp_ns\": 14702295507392,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14702295508864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 30,\n \"timestamp_ns\": 14702295508864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14700578871168,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14700578881152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14700578881984,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14700578895744,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14700578896192,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14700578905664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14700578905664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoCreate\", \"goroutine_id\": 11}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14700578871168,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14700578881152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14700578881984,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14700578895744,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14700578896192,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14700578905664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14700578905664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoCreate\", \"goroutine_id\": 39}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14700578871168,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14700578881152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14700578881984,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14700578895744,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14700578896192,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14700578905664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14700578905664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoCreate\", \"goroutine_id\": 39}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14700578871168,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14700578881152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14700578881984,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14700578895744,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14700578896192,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14700578905664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14700578905664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoCreate\", \"goroutine_id\": 12}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14700578871168,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14700578881152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14700578881984,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14700578895744,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14700578896192,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14700578905664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14700578905664,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoCreate\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14699559200832,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14699559203264,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14699559204416,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14699559205696,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14699559207360,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14699559207872,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14699559213504,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14699559213888,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14699559216832,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14699559217600,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 14,\n \"timestamp_ns\": 14699559217600,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoEnd\", \"goroutine_id\": 11}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14699559200832,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14699559203264,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14699559204416,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14699559205696,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14699559207360,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14699559207872,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14699559213504,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14699559213888,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14699559216832,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14699559217600,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 14,\n \"timestamp_ns\": 14699559217600,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoEnd\", \"goroutine_id\": 7}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14699559200832,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14699559203264,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14699559204416,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14699559205696,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14699559207360,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14699559207872,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14699559213504,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14699559213888,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14699559216832,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14699559217600,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 14,\n \"timestamp_ns\": 14699559217600,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoEnd\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14699559200832,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14699559203264,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14699559204416,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14699559205696,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14699559207360,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14699559207872,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14699559213504,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14699559213888,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14699559216832,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14699559217600,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 14,\n \"timestamp_ns\": 14699559217600,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 40}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14699559200832,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14699559203264,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14699559204416,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14699559205696,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14699559207360,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14699559207872,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14699559213504,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14699559213888,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14699559216832,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14699559217600,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 14,\n \"timestamp_ns\": 14699559217600,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoEnd\", \"goroutine_id\": 39}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14701595921536,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14701595921792,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14701595924160,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14701595928320,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 35,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14701595928896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14701595930496,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14701595931072,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 41,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14701595935488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14701595936320,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14701595936576,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 41,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14701595936576,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 41,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14701595921536,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14701595921792,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14701595924160,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14701595928320,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 35,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14701595928896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14701595930496,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14701595931072,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 41,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14701595935488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14701595936320,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14701595936576,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 41,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14701595936576,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 41,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 36}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14701595921536,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14701595921792,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14701595924160,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14701595928320,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 35,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14701595928896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14701595930496,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14701595931072,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 41,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14701595935488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14701595936320,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14701595936576,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 41,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14701595936576,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 41,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoEnd\", \"goroutine_id\": 11}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14701595921536,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14701595921792,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14701595924160,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14701595928320,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 35,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14701595928896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14701595930496,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14701595931072,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 41,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14701595935488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14701595936320,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14701595936576,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 41,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14701595936576,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 41,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoEnd\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: mutex\n// goroutine_count: 5\n// expected_nondeterminism: medium\n// description: four goroutines increment a shared counter protected by sync.Mutex, main prints final value.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar mu sync.Mutex\n\tcounter := 0\n\tvar wg sync.WaitGroup\n\n\tfor i := 0; i < 4; i++ {\n\t\twg.Add(1)\n\t\tgo func() {\n\t\t\tdefer wg.Done()\n\t\t\tfor j := 0; j < 5; j++ {\n\t\t\t\tmu.Lock()\n\t\t\t\tcounter++\n\t\t\t\tmu.Unlock()\n\t\t\t}\n\t\t}()\n\t}\n\n\twg.Wait()\n\tfmt.Println(counter)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14701595921536,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14701595921792,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14701595924160,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14701595928320,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 35,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14701595928896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14701595930496,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14701595931072,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 41,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14701595935488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14701595936320,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14701595936576,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 41,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14701595936576,\n \"event_type\": \"GoEnd\",\n \"goroutine_id\": 41,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14699839704000,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14699839709440,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14699839717120,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14699839750080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14699839760448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14699839773312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14699839773312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14699839704000,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14699839709440,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14699839717120,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14699839750080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14699839760448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14699839773312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14699839773312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 19}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14699839704000,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14699839709440,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14699839717120,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14699839750080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14699839760448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14699839773312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14699839773312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 35}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14699839704000,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14699839709440,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14699839717120,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14699839750080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14699839760448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14699839773312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14699839773312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14699839704000,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14699839709440,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14699839717120,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14699839750080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14699839760448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14699839773312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14699839773312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 4}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14702906533888,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14702906541056,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14702906543296,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14702906555904,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 37,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14702906564224,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14702906568064,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14702906571392,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14702906572160,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14702906588416,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14702906592192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14702906592896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14702906602624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 11,\n \"timestamp_ns\": 14702906602624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 37}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14702906533888,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14702906541056,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14702906543296,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14702906555904,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 37,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14702906564224,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14702906568064,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14702906571392,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14702906572160,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14702906588416,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14702906592192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14702906592896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14702906602624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 11,\n \"timestamp_ns\": 14702906602624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14702906533888,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14702906541056,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14702906543296,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14702906555904,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 37,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14702906564224,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14702906568064,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14702906571392,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14702906572160,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14702906588416,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14702906592192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14702906592896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14702906602624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 11,\n \"timestamp_ns\": 14702906602624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 7}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14702906533888,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14702906541056,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14702906543296,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14702906555904,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 37,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14702906564224,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14702906568064,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14702906571392,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14702906572160,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14702906588416,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14702906592192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14702906592896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14702906602624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 11,\n \"timestamp_ns\": 14702906602624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 22}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14702906533888,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14702906541056,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14702906543296,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14702906555904,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 37,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14702906564224,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14702906568064,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14702906571392,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 35,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14702906572160,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14702906588416,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14702906592192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14702906592896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14702906602624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 11,\n \"timestamp_ns\": 14702906602624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14700862091392,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14700862106368,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14700862106688,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14700862126784,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14700862127104,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14700862166656,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14700862175232,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14700862177792,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14700862183168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14700862183872,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14700862183872,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 22}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14700862091392,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14700862106368,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14700862106688,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14700862126784,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14700862127104,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14700862166656,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14700862175232,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14700862177792,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14700862183168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14700862183872,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14700862183872,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 22}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14700862091392,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14700862106368,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14700862106688,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14700862126784,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14700862127104,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14700862166656,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14700862175232,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14700862177792,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14700862183168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14700862183872,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14700862183872,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 7}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14700862091392,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14700862106368,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14700862106688,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14700862126784,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14700862127104,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14700862166656,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14700862175232,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14700862177792,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14700862183168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14700862183872,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14700862183872,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 38}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: success\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: buffered channel (cap=1) prevents goroutine leak on timeout; this is the fixed version of 06_channel_select (Kubernetes finishReq fix, Tu et al. ASPLOS'19).\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\n// fastWork completes well within the timeout.\nfunc fastWork() int {\n\ttime.Sleep(1 * time.Millisecond)\n\treturn 42\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\t// FIX: buffered channel with cap=1 ensures the child goroutine can always send\n\t// even if the parent has already returned via timeout. No goroutine is leaked.\n\tch := make(chan int, 1)\n\tgo func() {\n\t\tresult := fastWork()\n\t\tch <- result // never blocks \u2014 buffer absorbs the send if parent timed out\n\t}()\n\n\tselect {\n\tcase result := <-ch:\n\t\tfmt.Println(\"got:\", result)\n\tcase <-time.After(50 * time.Millisecond):\n\t\tfmt.Println(\"timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14700862091392,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14700862106368,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14700862106688,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14700862126784,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14700862127104,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14700862166656,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14700862175232,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14700862177792,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14700862183168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14700862183872,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14700862183872,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 22}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14707902361536,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14707902365824,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14707902372992,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14707902376512,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14707902384320,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14707902387264,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14707902390208,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14707902391488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14707902392000,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 8,\n \"timestamp_ns\": 14707902392000,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14707902361536,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14707902365824,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14707902372992,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14707902376512,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14707902384320,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14707902387264,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14707902390208,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14707902391488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14707902392000,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 8,\n \"timestamp_ns\": 14707902392000,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 20}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14707902361536,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14707902365824,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14707902372992,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14707902376512,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14707902384320,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14707902387264,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14707902390208,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14707902391488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14707902392000,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 8,\n \"timestamp_ns\": 14707902392000,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14707902361536,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14707902365824,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14707902372992,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14707902376512,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14707902384320,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14707902387264,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14707902390208,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14707902391488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14707902392000,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 8,\n \"timestamp_ns\": 14707902392000,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14707902361536,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14707902365824,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14707902372992,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14707902376512,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14707902384320,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14707902387264,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14707902390208,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14707902391488,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14707902392000,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 8,\n \"timestamp_ns\": 14707902392000,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"11\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14706833802496,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14706833812544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14706833816768,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14706833818432,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14706833819072,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14706833821696,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14706833822080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14706833823104,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14706833823424,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14706833823616,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14706833823616,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14706833802496,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14706833812544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14706833816768,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14706833818432,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14706833819072,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14706833821696,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14706833822080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14706833823104,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14706833823424,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14706833823616,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14706833823616,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 11}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14706833802496,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14706833812544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14706833816768,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14706833818432,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14706833819072,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14706833821696,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14706833822080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14706833823104,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14706833823424,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14706833823616,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14706833823616,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14706833802496,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14706833812544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14706833816768,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14706833818432,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14706833819072,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14706833821696,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14706833822080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14706833823104,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14706833823424,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14706833823616,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14706833823616,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 23}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14706833802496,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14706833812544,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14706833816768,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14706833818432,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14706833819072,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14706833821696,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14706833822080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14706833823104,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14706833823424,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14706833823616,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 18,\n \"timestamp_ns\": 14706833823616,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 35}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14708974025856,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14708974026112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14708974033344,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14708974036416,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14708974037184,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14708974038080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14708974038720,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14708974039680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14708974043968,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14708974044864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 27,\n \"timestamp_ns\": 14708974044864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14708974025856,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14708974026112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14708974033344,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14708974036416,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14708974037184,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14708974038080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14708974038720,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14708974039680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14708974043968,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14708974044864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 27,\n \"timestamp_ns\": 14708974044864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 35}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14708974025856,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14708974026112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14708974033344,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14708974036416,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14708974037184,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14708974038080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14708974038720,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14708974039680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14708974043968,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14708974044864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 27,\n \"timestamp_ns\": 14708974044864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14708974025856,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14708974026112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14708974033344,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14708974036416,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14708974037184,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14708974038080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14708974038720,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14708974039680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14708974043968,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14708974044864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 27,\n \"timestamp_ns\": 14708974044864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 3\n// expected_nondeterminism: none\n// description: two handler goroutines range over a requests channel; main sends a few items then exits without closing the channel, leaving handlers permanently blocked.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\trequests := make(chan int)\n\n\t// Two handler goroutines read from requests. They will block in GoWaiting\n\t// once main stops sending, because main never calls close(requests).\n\tfor i := 0; i < 2; i++ {\n\t\tgo func(id int) {\n\t\t\tfor req := range requests {\n\t\t\t\tfmt.Printf(\"handler %d processed request %d\\n\", id, req)\n\t\t\t}\n\t\t}(i)\n\t}\n\n\t// Send three requests then stop \u2014 handlers are left waiting for more.\n\tfor i := 0; i < 3; i++ {\n\t\trequests <- i\n\t}\n\n\t// Sleep so the trace captures both goroutines in GoWaiting before main exits.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14708974025856,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14708974026112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14708974033344,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14708974036416,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14708974037184,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14708974038080,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14708974038720,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14708974039680,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14708974043968,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14708974044864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 27,\n \"timestamp_ns\": 14708974044864,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14706389342400,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14706389346880,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14706389355968,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14706389364928,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14706389384192,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14706389414464,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14706389416320,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14706389416448,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14706389416896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14706389426432,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14706389435328,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14706389443840,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14706389456128,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 12,\n \"timestamp_ns\": 14706389456128,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14706389342400,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14706389346880,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14706389355968,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14706389364928,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14706389384192,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14706389414464,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14706389416320,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14706389416448,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14706389416896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14706389426432,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14706389435328,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14706389443840,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14706389456128,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 12,\n \"timestamp_ns\": 14706389456128,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 23}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14706389342400,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14706389346880,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14706389355968,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14706389364928,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14706389384192,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14706389414464,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14706389416320,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14706389416448,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14706389416896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14706389426432,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14706389435328,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14706389443840,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14706389456128,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 12,\n \"timestamp_ns\": 14706389456128,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 7}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14706389342400,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14706389346880,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14706389355968,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14706389364928,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14706389384192,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14706389414464,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14706389416320,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14706389416448,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14706389416896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14706389426432,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14706389435328,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14706389443840,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14706389456128,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 12,\n \"timestamp_ns\": 14706389456128,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14706389342400,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14706389346880,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14706389355968,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14706389364928,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14706389384192,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14706389414464,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14706389416320,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14706389416448,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14706389416896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14706389426432,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14706389435328,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14706389443840,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14706389456128,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 12,\n \"timestamp_ns\": 14706389456128,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv2\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14709654060288,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14709654069056,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14709654146944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14709654163328,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14709654197568,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14709658277440,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14709658286976,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14709658290944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14709663620544,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14709663626112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"5\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"6\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 27,\n \"timestamp_ns\": 14709663626112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"5\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"6\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 8}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14709654060288,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14709654069056,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14709654146944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14709654163328,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14709654197568,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14709658277440,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14709658286976,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14709658290944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14709663620544,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14709663626112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"5\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"6\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 27,\n \"timestamp_ns\": 14709663626112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"5\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"6\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14709654060288,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14709654069056,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14709654146944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14709654163328,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14709654197568,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14709658277440,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14709658286976,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14709658290944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14709663620544,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14709663626112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"5\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"6\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 27,\n \"timestamp_ns\": 14709663626112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"5\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"6\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14709654060288,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14709654069056,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14709654146944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14709654163328,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14709654197568,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14709658277440,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14709658286976,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14709658290944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14709663620544,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14709663626112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"5\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"6\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 27,\n \"timestamp_ns\": 14709663626112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"5\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"6\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14709654060288,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14709654069056,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14709654146944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14709654163328,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14709654197568,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14709658277440,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14709658286976,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14709658290944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14709663620544,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 27,\n \"timestamp_ns\": 14709663626112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"5\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"6\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 27,\n \"timestamp_ns\": 14709663626112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"5\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"6\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 24}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 29,\n \"timestamp_ns\": 14707493312192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14707503736000,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14707503741184,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14707503763520,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14707503784896,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14707503784960,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14707503790272,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14707513741952,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14707513747712,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14707513770112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"24\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 38,\n \"timestamp_ns\": 14707513770112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"24\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 24}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 29,\n \"timestamp_ns\": 14707493312192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14707503736000,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14707503741184,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14707503763520,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14707503784896,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14707503784960,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14707503790272,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14707513741952,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14707513747712,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14707513770112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"24\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 38,\n \"timestamp_ns\": 14707513770112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"24\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 29,\n \"timestamp_ns\": 14707493312192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14707503736000,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14707503741184,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14707503763520,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14707503784896,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14707503784960,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14707503790272,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14707513741952,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14707513747712,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14707513770112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"24\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 38,\n \"timestamp_ns\": 14707513770112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"24\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 29,\n \"timestamp_ns\": 14707493312192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14707503736000,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14707503741184,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14707503763520,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14707503784896,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14707503784960,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14707503790272,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14707513741952,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14707513747712,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14707513770112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"24\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 38,\n \"timestamp_ns\": 14707513770112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"24\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 8}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: channel\n// goroutine_count: 2\n// expected_nondeterminism: none\n// description: goroutine reads from time.Ticker.C in a loop; main never calls ticker.Stop() and exits, leaving the goroutine permanently blocked on the ticker channel.\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tticker := time.NewTicker(10 * time.Millisecond)\n\n\t// Goroutine reads tick events. It will block on ticker.C between ticks.\n\t// BUG: main never calls ticker.Stop(); the goroutine is left alive and\n\t// permanently cycling between GoWaiting and GoRunnable when main exits.\n\tgo func() {\n\t\tfor t := range ticker.C {\n\t\t\tfmt.Println(\"tick at\", t.UnixMilli())\n\t\t}\n\t}()\n\n\t// Let one tick fire so the goroutine runs at least once.\n\ttime.Sleep(15 * time.Millisecond)\n\n\t// Exit without ticker.Stop() or closing ticker.C \u2014 goroutine leaks.\n\ttime.Sleep(50 * time.Millisecond)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 29,\n \"timestamp_ns\": 14707493312192,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14707503736000,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14707503741184,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14707503763520,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14707503784896,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14707503784960,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14707503790272,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14707513741952,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14707513747712,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 24,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14707513770112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"24\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 38,\n \"timestamp_ns\": 14707513770112,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"23\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"24\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14718608335104,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14718608342912,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14718608348736,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14718608352064,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14718608355328,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14718608355904,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14718608358208,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14718608358720,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14718608374656,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14718608375168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 13,\n \"timestamp_ns\": 14718608375168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 12}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14718608335104,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14718608342912,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14718608348736,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14718608352064,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14718608355328,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14718608355904,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14718608358208,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14718608358720,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14718608374656,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14718608375168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 13,\n \"timestamp_ns\": 14718608375168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 23}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14718608335104,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14718608342912,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14718608348736,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14718608352064,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14718608355328,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14718608355904,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14718608358208,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14718608358720,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14718608374656,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14718608375168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 13,\n \"timestamp_ns\": 14718608375168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 12}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14718608335104,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14718608342912,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14718608348736,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14718608352064,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14718608355328,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14718608355904,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14718608358208,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14718608358720,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14718608374656,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14718608375168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 13,\n \"timestamp_ns\": 14718608375168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 11}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14718608335104,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14718608342912,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14718608348736,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14718608352064,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14718608355328,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14718608355904,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14718608358208,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14718608358720,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14718608374656,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14718608375168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 13,\n \"timestamp_ns\": 14718608375168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 24}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14717394793152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14717394796288,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14717394797120,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14717394797568,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14717394797696,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14717394800896,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14717394800960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14717394801408,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14717394803584,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14717394804992,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"11\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 26,\n \"timestamp_ns\": 14717394804992,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"11\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoEnd\", \"goroutine_id\": 12}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14717394793152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14717394796288,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14717394797120,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14717394797568,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14717394797696,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14717394800896,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14717394800960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14717394801408,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14717394803584,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14717394804992,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"11\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 26,\n \"timestamp_ns\": 14717394804992,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"11\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 25}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14717394793152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14717394796288,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14717394797120,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14717394797568,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14717394797696,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14717394800896,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14717394800960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14717394801408,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14717394803584,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14717394804992,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"11\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 26,\n \"timestamp_ns\": 14717394804992,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"11\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14717394793152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14717394796288,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14717394797120,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14717394797568,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14717394797696,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14717394800896,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14717394800960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14717394801408,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14717394803584,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14717394804992,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"11\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 26,\n \"timestamp_ns\": 14717394804992,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"11\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14717394793152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14717394796288,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14717394797120,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14717394797568,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14717394797696,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14717394800896,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14717394800960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14717394801408,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14717394803584,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14717394804992,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"11\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 26,\n \"timestamp_ns\": 14717394804992,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"11\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"12\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"13\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14721036581056,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14721036581696,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14721037610176,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14721037610432,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14721037612608,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14721037617280,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14721037618944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14721037622784,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 39,\n \"timestamp_ns\": 14721037627776,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 40,\n \"timestamp_ns\": 14721037628224,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 40,\n \"timestamp_ns\": 14721037628224,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 23}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14721036581056,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14721036581696,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14721037610176,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14721037610432,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14721037612608,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14721037617280,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14721037618944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14721037622784,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 39,\n \"timestamp_ns\": 14721037627776,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 40,\n \"timestamp_ns\": 14721037628224,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 40,\n \"timestamp_ns\": 14721037628224,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14721036581056,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14721036581696,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14721037610176,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14721037610432,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14721037612608,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14721037617280,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14721037618944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14721037622784,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 39,\n \"timestamp_ns\": 14721037627776,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 40,\n \"timestamp_ns\": 14721037628224,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 40,\n \"timestamp_ns\": 14721037628224,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14721036581056,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14721036581696,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14721037610176,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14721037610432,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14721037612608,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14721037617280,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14721037618944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14721037622784,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 39,\n \"timestamp_ns\": 14721037627776,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 40,\n \"timestamp_ns\": 14721037628224,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 40,\n \"timestamp_ns\": 14721037628224,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 22}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14721036581056,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14721036581696,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14721037610176,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14721037610432,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14721037612608,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14721037617280,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14721037618944,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14721037622784,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 39,\n \"timestamp_ns\": 14721037627776,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 40,\n \"timestamp_ns\": 14721037628224,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 40,\n \"timestamp_ns\": 14721037628224,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 11}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14722742687040,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14722742688448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14722742692160,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14722742696000,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14722742699456,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14722742711744,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14722742712384,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14722742713600,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14722742713984,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14722742714048,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 13,\n \"timestamp_ns\": 14722742714048,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 12}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14722742687040,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14722742688448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14722742692160,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14722742696000,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14722742699456,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14722742711744,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14722742712384,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14722742713600,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14722742713984,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14722742714048,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 13,\n \"timestamp_ns\": 14722742714048,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 20}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14722742687040,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14722742688448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14722742692160,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14722742696000,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14722742699456,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14722742711744,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14722742712384,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14722742713600,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14722742713984,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14722742714048,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 13,\n \"timestamp_ns\": 14722742714048,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 22}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14722742687040,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14722742688448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14722742692160,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14722742696000,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14722742699456,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14722742711744,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14722742712384,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14722742713600,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14722742713984,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14722742714048,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 13,\n \"timestamp_ns\": 14722742714048,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 36}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14722742687040,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14722742688448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14722742692160,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 11,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14722742696000,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 12,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14722742699456,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 13,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14722742711744,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14722742712384,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14722742713600,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14722742713984,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14722742714048,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 13,\n \"timestamp_ns\": 14722742714048,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 11,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"11\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"12\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"13\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14717862011776,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14717862014272,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14717862015168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14717862015744,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14717862016064,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14717862024448,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14717862024896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14717862030528,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14717862030848,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14717862031040,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"39\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"40\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"41\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 26,\n \"timestamp_ns\": 14717862031040,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"39\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"40\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"41\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 38}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14717862011776,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14717862014272,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14717862015168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14717862015744,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14717862016064,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14717862024448,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14717862024896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14717862030528,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14717862030848,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14717862031040,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"39\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"40\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"41\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 26,\n \"timestamp_ns\": 14717862031040,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"39\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"40\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"41\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14717862011776,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14717862014272,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14717862015168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14717862015744,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14717862016064,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14717862024448,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14717862024896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14717862030528,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14717862030848,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14717862031040,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"39\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"40\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"41\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 26,\n \"timestamp_ns\": 14717862031040,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"39\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"40\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"41\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14717862011776,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14717862014272,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14717862015168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14717862015744,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14717862016064,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14717862024448,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14717862024896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14717862030528,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14717862030848,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14717862031040,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"39\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"40\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"41\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 26,\n \"timestamp_ns\": 14717862031040,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"39\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"40\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"41\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 23}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14717862011776,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14717862014272,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 40,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14717862015168,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14717862015744,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 21,\n \"timestamp_ns\": 14717862016064,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 22,\n \"timestamp_ns\": 14717862024448,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 23,\n \"timestamp_ns\": 14717862024896,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 24,\n \"timestamp_ns\": 14717862030528,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 38,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 25,\n \"timestamp_ns\": 14717862030848,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 39,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 26,\n \"timestamp_ns\": 14717862031040,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"39\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"40\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"41\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 26,\n \"timestamp_ns\": 14717862031040,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 38,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"39\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan send\",\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"40\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"41\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoEnd\", \"goroutine_id\": 24}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14720310050688,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14720310085440,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14720310100736,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14720311159296,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14720311160192,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14720311164544,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14720311168960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14720311169472,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14720311172992,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 39,\n \"timestamp_ns\": 14720311176960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 39,\n \"timestamp_ns\": 14720311176960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 23}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14720310050688,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14720310085440,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14720310100736,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14720311159296,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14720311160192,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14720311164544,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14720311168960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14720311169472,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14720311172992,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 39,\n \"timestamp_ns\": 14720311176960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 39,\n \"timestamp_ns\": 14720311176960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14720310050688,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14720310085440,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14720310100736,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14720311159296,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14720311160192,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14720311164544,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14720311168960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14720311169472,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14720311172992,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 39,\n \"timestamp_ns\": 14720311176960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 39,\n \"timestamp_ns\": 14720311176960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 22}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14720310050688,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14720310085440,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14720310100736,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14720311159296,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14720311160192,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14720311164544,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14720311168960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14720311169472,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14720311172992,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 39,\n \"timestamp_ns\": 14720311176960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 39,\n \"timestamp_ns\": 14720311176960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: pipeline\n// goroutine_count: 4\n// expected_nondeterminism: medium\n// description: Pipeline pipeline stages stage1 -> stage2 -> stage3, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"sync\"\n\t\"time\"\n)\n\nfunc stage1(out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor i := 0; i < 5; i++ {\n\t\tout <- i\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc stage2(in <-chan int, out chan<- int, wg *sync.WaitGroup) {\n\tdefer wg.Done()\n\tfor v := range in {\n\t\tout <- v * 2\n\t\ttime.Sleep(time.Millisecond * 1)\n\t}\n\tclose(out)\n}\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tvar wg1, wg2, wg3 sync.WaitGroup\n\tch1 := make(chan int)\n\tch2 := make(chan int)\n\n\twg1.Add(1)\n\tgo stage1(ch1, &wg1)\n\n\twg2.Add(1)\n\tgo stage2(ch1, ch2, &wg2)\n\n\twg3.Add(1)\n\tgo func(inCh <-chan int) {\n\t\tdefer wg3.Done()\n\t\t\t// Bug: exit early after 1 item, leaving stage2 blocked\n\tval := <-inCh\n\t_ = val\n\t}(ch2)\n\n\t// Exit harness\n\tdone := make(chan struct{})\n\tgo func() {\n\t\twg1.Wait()\n\t\twg2.Wait()\n\t\twg3.Wait()\n\t\tclose(done)\n\t}()\n\n\tselect {\n\tcase <-done:\n\t\tfmt.Println(\"pipeline done\")\n\tcase <-time.After(200 * time.Millisecond):\n\t\tfmt.Println(\"pipeline timeout\")\n\t}\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 30,\n \"timestamp_ns\": 14720310050688,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 19,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 31,\n \"timestamp_ns\": 14720310085440,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 32,\n \"timestamp_ns\": 14720310100736,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 33,\n \"timestamp_ns\": 14720311159296,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 34,\n \"timestamp_ns\": 14720311160192,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 35,\n \"timestamp_ns\": 14720311164544,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 36,\n \"timestamp_ns\": 14720311168960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 37,\n \"timestamp_ns\": 14720311169472,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 38,\n \"timestamp_ns\": 14720311172992,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 23,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 39,\n \"timestamp_ns\": 14720311176960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 39,\n \"timestamp_ns\": 14720311176960,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.chansend1\"\n },\n \"25\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sync\",\n \"locals_hint\": \"sync.(*WaitGroup).Wait\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 38}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14718975057024,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14718975061312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14718975061824,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14718975073152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14718975104448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14718975109312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14718975116288,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 6,\n \"timestamp_ns\": 14718975116288,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 19}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14718975057024,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14718975061312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14718975061824,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14718975073152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14718975104448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14718975109312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14718975116288,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 6,\n \"timestamp_ns\": 14718975116288,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14718975057024,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14718975061312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14718975061824,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14718975073152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14718975104448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14718975109312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14718975116288,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 6,\n \"timestamp_ns\": 14718975116288,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14718975057024,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14718975061312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14718975061824,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14718975073152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14718975104448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14718975109312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14718975116288,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 6,\n \"timestamp_ns\": 14718975116288,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14718975057024,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14718975061312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14718975061824,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14718975073152,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14718975104448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14718975109312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14718975116288,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 6,\n \"timestamp_ns\": 14718975116288,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14723148740864,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14723148749312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14723148760448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14723148764352,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14723148764992,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14723148797824,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14723148819456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14723148825024,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14723148826112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14723148840704,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14723148853824,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14723148854720,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14723148856448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 12,\n \"timestamp_ns\": 14723148856448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14723148740864,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14723148749312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14723148760448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14723148764352,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14723148764992,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14723148797824,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14723148819456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14723148825024,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14723148826112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14723148840704,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14723148853824,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14723148854720,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14723148856448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 12,\n \"timestamp_ns\": 14723148856448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14723148740864,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14723148749312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14723148760448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14723148764352,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14723148764992,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14723148797824,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14723148819456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14723148825024,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14723148826112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14723148840704,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14723148853824,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14723148854720,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14723148856448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 12,\n \"timestamp_ns\": 14723148856448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14723148740864,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14723148749312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14723148760448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14723148764352,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14723148764992,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14723148797824,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14723148819456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14723148825024,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14723148826112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14723148840704,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14723148853824,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14723148854720,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14723148856448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 12,\n \"timestamp_ns\": 14723148856448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14723148740864,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14723148749312,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14723148760448,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14723148764352,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14723148764992,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14723148797824,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14723148819456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14723148825024,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 20,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14723148826112,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14723148840704,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14723148853824,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14723148854720,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 19,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14723148856448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 12,\n \"timestamp_ns\": 14723148856448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"19\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"20\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 37}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14720017920384,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14720017920448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14720017923136,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14720017927104,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14720017927744,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14720017927936,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14720017944704,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14720019040512,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14720019042688,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14720019063232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 20,\n \"timestamp_ns\": 14720019063232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoUnblock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14720017920384,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14720017920448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14720017923136,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14720017927104,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14720017927744,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14720017927936,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14720017944704,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14720019040512,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14720019042688,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14720019063232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 20,\n \"timestamp_ns\": 14720019063232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14720017920384,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14720017920448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14720017923136,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14720017927104,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14720017927744,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14720017927936,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14720017944704,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14720019040512,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14720019042688,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14720019063232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 20,\n \"timestamp_ns\": 14720019063232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoBlock\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14720017920384,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14720017920448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14720017923136,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14720017927104,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14720017927744,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14720017927936,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14720017944704,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14720019040512,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14720019042688,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14720019063232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 20,\n \"timestamp_ns\": 14720019063232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14720017920384,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14720017920448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14720017923136,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14720017927104,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 15,\n \"timestamp_ns\": 14720017927744,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 16,\n \"timestamp_ns\": 14720017927936,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 37,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 17,\n \"timestamp_ns\": 14720017944704,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 36,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 18,\n \"timestamp_ns\": 14720019040512,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 19,\n \"timestamp_ns\": 14720019042688,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 1,\n \"goroutines\": \"... [TRUNCATED FOR LENGTH] ...\",\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 20,\n \"timestamp_ns\": 14720019063232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 20,\n \"timestamp_ns\": 14720019063232,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n },\n \"35\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"36\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"37\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"system goroutine wait\",\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked.func1\"\n },\n \"38\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 1}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14727426188608,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14727426197568,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14727426207424,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14727426213760,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14727426217856,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14727426235456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14727426235456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 23}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14727426188608,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14727426197568,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14727426207424,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14727426213760,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14727426217856,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14727426235456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14727426235456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14727426188608,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14727426197568,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14727426207424,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14727426213760,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14727426217856,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14727426235456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14727426235456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 21}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14727426188608,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14727426197568,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14727426207424,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14727426213760,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14727426217856,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14727426235456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14727426235456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 10}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14727426188608,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14727426197568,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 22,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14727426207424,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 21,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14727426213760,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 23,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14727426217856,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 24,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14727426235456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 5,\n \"timestamp_ns\": 14727426235456,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"21\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"22\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n },\n \"23\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n },\n \"24\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoStart\", \"goroutine_id\": 6}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14726385218816,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14726385223616,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14726385224448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14726385235136,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14726385235648,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14726385241280,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14726385258624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14726385259008,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14726385260608,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14726385260992,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14726385261376,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14726385266048,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14726385290368,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14726385332672,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14726385332736,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 14,\n \"timestamp_ns\": 14726385332736,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"\",\"confidence\":\"high|medium|low\"}"}, {"role": "assistant", "content": "{\"event_type\": \"GoSched\", \"goroutine_id\": 9}"}]}
{"messages": [{"role": "system", "content": "You are a code execution simulator."}, {"role": "user", "content": "You are reasoning about concurrent Go program execution.\n\nHere is a Go program:\n\n// WEAVE_META\n// outcome: leak\n// concurrency_pattern: select\n// goroutine_count: 2\n// expected_nondeterminism: low\n// description: Select statement on unbuffered channel, leak_bug=True\n\npackage main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\t\"runtime/trace\"\n\t\"time\"\n)\n\nfunc main() {\n\tif tf := os.Getenv(\"WEAVE_TRACE_FILE\"); tf != \"\" {\n\t\tf, err := os.Create(tf)\n\t\tif err == nil {\n\t\t\tif err := trace.Start(f); err == nil {\n\t\t\t\tdefer func() { trace.Stop(); f.Close() }()\n\t\t\t}\n\t\t}\n\t}\n\n\tch := make(chan int)\n\n\tgo func() {\n\t\t// Simulate processing delay\n\t\ttime.Sleep(time.Millisecond * 10)\n\t\tch <- 42\n\t}()\n\n\tselect {\n\tcase val := <-ch:\n\t\tfmt.Println(\"received:\", val)\n\tcase <-time.After(1 * time.Millisecond):\n\t\tfmt.Println(\"timeout occurred\")\n\t}\n\n\t// Small delay to allow the leaked goroutine to lock into GoWaiting block\n\ttime.Sleep(time.Millisecond * 20)\n}\n\n\n\nHere is a partial execution trace showing goroutine scheduler events so far:\n\n[\n {\n \"event_id\": 0,\n \"timestamp_ns\": 14726385218816,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 1,\n \"timestamp_ns\": 14726385223616,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.traceStartReadCPU\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 2,\n \"timestamp_ns\": 14726385224448,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime.(*traceAdvancerState).start\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 3,\n \"timestamp_ns\": 14726385235136,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 4,\n \"timestamp_ns\": 14726385235648,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 5,\n \"timestamp_ns\": 14726385241280,\n \"event_type\": \"GoCreate\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 6,\n \"timestamp_ns\": 14726385258624,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 1,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"main.main\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 7,\n \"timestamp_ns\": 14726385259008,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 8,\n \"timestamp_ns\": 14726385260608,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 8,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"runtime/trace.(*traceMultiplexer).startLocked\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 9,\n \"timestamp_ns\": 14726385260992,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 10,\n \"timestamp_ns\": 14726385261376,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 7,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 11,\n \"timestamp_ns\": 14726385266048,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 10,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 12,\n \"timestamp_ns\": 14726385290368,\n \"event_type\": \"GoBlock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": \"syscall\",\n \"locals_hint\": \"syscall.syscall\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 13,\n \"timestamp_ns\": 14726385332672,\n \"event_type\": \"GoUnblock\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"runnable\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n },\n {\n \"event_id\": 14,\n \"timestamp_ns\": 14726385332736,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n }\n]\n\n\nThe current goroutine states are:\n\n{\n \"event_id\": 14,\n \"timestamp_ns\": 14726385332736,\n \"event_type\": \"GoStart\",\n \"goroutine_id\": 9,\n \"goroutines\": {\n \"1\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"select\",\n \"locals_hint\": \"runtime.selectgo\"\n },\n \"10\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"sleep\",\n \"locals_hint\": \"time.Sleep\"\n },\n \"7\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"8\": {\n \"status\": \"blocked\",\n \"blocked_on\": \"chan receive\",\n \"locals_hint\": \"runtime.chanrecv1\"\n },\n \"9\": {\n \"status\": \"running\",\n \"blocked_on\": null,\n \"locals_hint\": \"unknown\"\n }\n },\n \"channels\": {},\n \"mutexes\": {}\n}\n\n\nPredict the next scheduler event. What happens next?\nRespond in JSON only \u2014 no markdown fences, no text outside the JSON object:\n{\"event_type\":\"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched\",\"goroutine_id\":,\"reasoning\":\"