[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14785236736640,
    "event_type": "GoCreate",
    "goroutine_id": 21,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "21": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14785236741248,
    "event_type": "GoCreate",
    "goroutine_id": 22,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "21": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "22": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14785236747136,
    "event_type": "GoCreate",
    "goroutine_id": 23,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "21": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "22": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "23": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14785236747840,
    "event_type": "GoStart",
    "goroutine_id": 21,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "21": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "22": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "23": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14785236750656,
    "event_type": "GoCreate",
    "goroutine_id": 24,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "21": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "22": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "23": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "24": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14785236755072,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "21": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "22": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "23": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "24": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 5,
  "timestamp_ns": 14785236755072,
  "event_type": "GoBlock",
  "goroutine_id": 1,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "sync",
      "locals_hint": "sync.(*WaitGroup).Wait"
    },
    "21": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "22": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "runtime.(*traceAdvancerState).start"
    },
    "23": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
    },
    "24": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoBlock", "goroutine_id": 1}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14785236736640,
    "event_type": "GoCreate",
    "goroutine_id": 21,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "21": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14785236741248,
    "event_type": "GoCreate",
    "goroutine_id": 22,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "21": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "22": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14785236747136,
    "event_type": "GoCreate",
    "goroutine_id": 23,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "21": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "22": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "23": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14785236747840,
    "event_type": "GoStart",
    "goroutine_id": 21,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "21": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "22": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "23": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14785236750656,
    "event_type": "GoCreate",
    "goroutine_id": 24,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "21": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "22": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "23": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "24": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14785236755072,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "21": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "22": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "23": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "24": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 5,
  "timestamp_ns": 14785236755072,
  "event_type": "GoBlock",
  "goroutine_id": 1,
  "goroutines": {
    "1": {
      "status": "blocked",
      "blocked_on": "sync",
      "locals_hint": "sync.(*WaitGroup).Wait"
    },
    "21": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "22": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "runtime.(*traceAdvancerState).start"
    },
    "23": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
    },
    "24": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "main.main"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoBlock", "goroutine_id": 1}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14782172632832,
    "event_type": "GoCreate",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14782172637440,
    "event_type": "GoCreate",
    "goroutine_id": 5,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14782172645824,
    "event_type": "GoStart",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14782172660992,
    "event_type": "GoCreate",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14782172665984,
    "event_type": "GoCreate",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14782172669696,
    "event_type": "GoStart",
    "goroutine_id": 5,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 6,
    "timestamp_ns": 14782172670208,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 7,
    "timestamp_ns": 14782172670656,
    "event_type": "GoStart",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 8,
    "timestamp_ns": 14782172684736,
    "event_type": "GoStart",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 9,
    "timestamp_ns": 14782172708416,
    "event_type": "GoBlock",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14782172721536,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "sync.(*WaitGroup).Add"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14782172724416,
    "event_type": "GoBlock",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "sync.(*WaitGroup).Add"
      },
      "4": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 11,
  "timestamp_ns": 14782172724416,
  "event_type": "GoBlock",
  "goroutine_id": 4,
  "goroutines": {
    "1": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "sync.(*WaitGroup).Add"
    },
    "4": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "5": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "6": {
      "status": "running",
      "blocked_on": "syscall",
      "locals_hint": "syscall.syscall"
    },
    "7": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoCreate", "goroutine_id": 8}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14782172632832,
    "event_type": "GoCreate",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14782172637440,
    "event_type": "GoCreate",
    "goroutine_id": 5,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14782172645824,
    "event_type": "GoStart",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14782172660992,
    "event_type": "GoCreate",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14782172665984,
    "event_type": "GoCreate",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14782172669696,
    "event_type": "GoStart",
    "goroutine_id": 5,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 6,
    "timestamp_ns": 14782172670208,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 7,
    "timestamp_ns": 14782172670656,
    "event_type": "GoStart",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 8,
    "timestamp_ns": 14782172684736,
    "event_type": "GoStart",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 9,
    "timestamp_ns": 14782172708416,
    "event_type": "GoBlock",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14782172721536,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "sync.(*WaitGroup).Add"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14782172724416,
    "event_type": "GoBlock",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "sync.(*WaitGroup).Add"
      },
      "4": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 11,
  "timestamp_ns": 14782172724416,
  "event_type": "GoBlock",
  "goroutine_id": 4,
  "goroutines": {
    "1": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "sync.(*WaitGroup).Add"
    },
    "4": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "5": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "6": {
      "status": "running",
      "blocked_on": "syscall",
      "locals_hint": "syscall.syscall"
    },
    "7": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoStart", "goroutine_id": 9}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14782172632832,
    "event_type": "GoCreate",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14782172637440,
    "event_type": "GoCreate",
    "goroutine_id": 5,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14782172645824,
    "event_type": "GoStart",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14782172660992,
    "event_type": "GoCreate",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14782172665984,
    "event_type": "GoCreate",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14782172669696,
    "event_type": "GoStart",
    "goroutine_id": 5,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 6,
    "timestamp_ns": 14782172670208,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 7,
    "timestamp_ns": 14782172670656,
    "event_type": "GoStart",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 8,
    "timestamp_ns": 14782172684736,
    "event_type": "GoStart",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 9,
    "timestamp_ns": 14782172708416,
    "event_type": "GoBlock",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14782172721536,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "sync.(*WaitGroup).Add"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14782172724416,
    "event_type": "GoBlock",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "sync.(*WaitGroup).Add"
      },
      "4": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 11,
  "timestamp_ns": 14782172724416,
  "event_type": "GoBlock",
  "goroutine_id": 4,
  "goroutines": {
    "1": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "sync.(*WaitGroup).Add"
    },
    "4": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "5": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "6": {
      "status": "running",
      "blocked_on": "syscall",
      "locals_hint": "syscall.syscall"
    },
    "7": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoBlock", "goroutine_id": 21}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14782172632832,
    "event_type": "GoCreate",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14782172637440,
    "event_type": "GoCreate",
    "goroutine_id": 5,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14782172645824,
    "event_type": "GoStart",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14782172660992,
    "event_type": "GoCreate",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14782172665984,
    "event_type": "GoCreate",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14782172669696,
    "event_type": "GoStart",
    "goroutine_id": 5,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 6,
    "timestamp_ns": 14782172670208,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 7,
    "timestamp_ns": 14782172670656,
    "event_type": "GoStart",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 8,
    "timestamp_ns": 14782172684736,
    "event_type": "GoStart",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 9,
    "timestamp_ns": 14782172708416,
    "event_type": "GoBlock",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14782172721536,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "sync.(*WaitGroup).Add"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14782172724416,
    "event_type": "GoBlock",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "sync.(*WaitGroup).Add"
      },
      "4": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 11,
  "timestamp_ns": 14782172724416,
  "event_type": "GoBlock",
  "goroutine_id": 4,
  "goroutines": {
    "1": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "sync.(*WaitGroup).Add"
    },
    "4": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "5": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "6": {
      "status": "running",
      "blocked_on": "syscall",
      "locals_hint": "syscall.syscall"
    },
    "7": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoStart", "goroutine_id": 37}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 0,
    "timestamp_ns": 14782172632832,
    "event_type": "GoCreate",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 1,
    "timestamp_ns": 14782172637440,
    "event_type": "GoCreate",
    "goroutine_id": 5,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.traceStartReadCPU"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 2,
    "timestamp_ns": 14782172645824,
    "event_type": "GoStart",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 3,
    "timestamp_ns": 14782172660992,
    "event_type": "GoCreate",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 4,
    "timestamp_ns": 14782172665984,
    "event_type": "GoCreate",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime.(*traceAdvancerState).start"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 5,
    "timestamp_ns": 14782172669696,
    "event_type": "GoStart",
    "goroutine_id": 5,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 6,
    "timestamp_ns": 14782172670208,
    "event_type": "GoBlock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "main.main"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 7,
    "timestamp_ns": 14782172670656,
    "event_type": "GoStart",
    "goroutine_id": 7,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 8,
    "timestamp_ns": 14782172684736,
    "event_type": "GoStart",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 9,
    "timestamp_ns": 14782172708416,
    "event_type": "GoBlock",
    "goroutine_id": 6,
    "goroutines": {
      "1": {
        "status": "blocked",
        "blocked_on": "sync",
        "locals_hint": "sync.(*WaitGroup).Wait"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14782172721536,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "sync.(*WaitGroup).Add"
      },
      "4": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14782172724416,
    "event_type": "GoBlock",
    "goroutine_id": 4,
    "goroutines": {
      "1": {
        "status": "runnable",
        "blocked_on": null,
        "locals_hint": "sync.(*WaitGroup).Add"
      },
      "4": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "5": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "6": {
        "status": "running",
        "blocked_on": "syscall",
        "locals_hint": "syscall.syscall"
      },
      "7": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 11,
  "timestamp_ns": 14782172724416,
  "event_type": "GoBlock",
  "goroutine_id": 4,
  "goroutines": {
    "1": {
      "status": "runnable",
      "blocked_on": null,
      "locals_hint": "sync.(*WaitGroup).Add"
    },
    "4": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "5": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "6": {
      "status": "running",
      "blocked_on": "syscall",
      "locals_hint": "syscall.syscall"
    },
    "7": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoBlock", "goroutine_id": 9}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 8,
    "timestamp_ns": 14784211613824,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 9,
    "timestamp_ns": 14784211625536,
    "event_type": "GoBlock",
    "goroutine_id": 8,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14784211627776,
    "event_type": "GoBlock",
    "goroutine_id": 7,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14784211646464,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 12,
    "timestamp_ns": 14784211650688,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 13,
    "timestamp_ns": 14784211658176,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 14,
    "timestamp_ns": 14784211659328,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 15,
    "timestamp_ns": 14784211663168,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 16,
    "timestamp_ns": 14784211678272,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 17,
    "timestamp_ns": 14784211701568,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "8": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "9": {
        "status": "blocked",
        "blocked_on": "system goroutine wait",
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked.func1"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 17,
  "timestamp_ns": 14784211701568,
  "event_type": "GoStart",
  "goroutine_id": 1,
  "goroutines": {
    "1": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "10": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "7": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "8": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "9": {
      "status": "blocked",
      "blocked_on": "system goroutine wait",
      "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked.func1"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoCreate", "goroutine_id": 17}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 8,
    "timestamp_ns": 14784211613824,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 9,
    "timestamp_ns": 14784211625536,
    "event_type": "GoBlock",
    "goroutine_id": 8,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14784211627776,
    "event_type": "GoBlock",
    "goroutine_id": 7,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14784211646464,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 12,
    "timestamp_ns": 14784211650688,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 13,
    "timestamp_ns": 14784211658176,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 14,
    "timestamp_ns": 14784211659328,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 15,
    "timestamp_ns": 14784211663168,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 16,
    "timestamp_ns": 14784211678272,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 17,
    "timestamp_ns": 14784211701568,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "8": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "9": {
        "status": "blocked",
        "blocked_on": "system goroutine wait",
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked.func1"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 17,
  "timestamp_ns": 14784211701568,
  "event_type": "GoStart",
  "goroutine_id": 1,
  "goroutines": {
    "1": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "10": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "7": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "8": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "9": {
      "status": "blocked",
      "blocked_on": "system goroutine wait",
      "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked.func1"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoBlock", "goroutine_id": 23}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 8,
    "timestamp_ns": 14784211613824,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 9,
    "timestamp_ns": 14784211625536,
    "event_type": "GoBlock",
    "goroutine_id": 8,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14784211627776,
    "event_type": "GoBlock",
    "goroutine_id": 7,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14784211646464,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 12,
    "timestamp_ns": 14784211650688,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 13,
    "timestamp_ns": 14784211658176,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 14,
    "timestamp_ns": 14784211659328,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 15,
    "timestamp_ns": 14784211663168,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 16,
    "timestamp_ns": 14784211678272,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 17,
    "timestamp_ns": 14784211701568,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "8": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "9": {
        "status": "blocked",
        "blocked_on": "system goroutine wait",
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked.func1"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 17,
  "timestamp_ns": 14784211701568,
  "event_type": "GoStart",
  "goroutine_id": 1,
  "goroutines": {
    "1": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "10": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "7": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "8": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "9": {
      "status": "blocked",
      "blocked_on": "system goroutine wait",
      "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked.func1"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoStart", "goroutine_id": 1}


[System] You are a code execution simulator.

[User]
You are reasoning about concurrent Go program execution.

Here is a Go program:
<program>
// WEAVE_META
// outcome: race
// concurrency_pattern: mutex
// goroutine_count: 3
// expected_nondeterminism: medium
// description: Human-written GoBench bug kernel kubernetes_88331 (race)

package main

import (
	"os"
	"runtime/trace"
	"sync"
	)

type data struct {
	queue []struct{}
}

func (h *data) Pop() {
	h.queue = h.queue[0 : len(h.queue)-1]
}

type Interface interface {
	Pop()
}

func Pop(h Interface) {
	h.Pop()
}

type Heap struct {
	data *data
}

func (h *Heap) Pop() {
	Pop(h.data)
}
func (h *Heap) Len() int {
	return len(h.data.queue)
}

func NewWithRecorder() *Heap {
	return &Heap{
		data: &data{
			queue: []struct{}{
				struct{}{},
				struct{}{},
			},
		},
	}
}

type PriorityQueue struct {
	stop        chan struct{}
	lock        sync.RWMutex
	podBackoffQ *Heap
	activeQ     *Heap
}

func (p *PriorityQueue) flushBackoffQCompleted() {
	p.lock.Lock()
	defer p.lock.Unlock()
	p.podBackoffQ.Pop()

}

func NewPriorityQueue() *PriorityQueue {
	return &PriorityQueue{
		stop:        make(chan struct{}),
		activeQ:     NewWithRecorder(),
		podBackoffQ: NewWithRecorder(),
	}
}

func createAndRunPriorityQueue() *PriorityQueue {
	q := NewPriorityQueue()
	q.Run()
	return q
}

func (p *PriorityQueue) Run() {
	go Until(p.flushBackoffQCompleted, p.stop)
}

func BackoffUntil(f func(), stopCh <-chan struct{}) {
	for {
		select {
		case <-stopCh:
			return
		default:
		}

		func() {
			f()
		}()

		select {
		case <-stopCh:
			return
		}
	}
}

func JitterUntil(f func(), stopCh <-chan struct{}) {
	BackoffUntil(f, stopCh)
}

func Until(f func(), stopCh <-chan struct{}) {
	JitterUntil(f, stopCh)
}

func main() {
	if tf := os.Getenv("WEAVE_TRACE_FILE"); tf != "" {
		f, err := os.Create(tf)
		if err == nil {
			if err := trace.Start(f); err == nil {
				defer func() { trace.Stop(); f.Close() }()
			}
		}
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		wg.Done()
		p := createAndRunPriorityQueue()
		p.podBackoffQ.Len()
	}()
	wg.Wait()
}

</program>

Here is a partial execution trace showing goroutine scheduler events so far:
<trace>
[
  {
    "event_id": 8,
    "timestamp_ns": 14784211613824,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 9,
    "timestamp_ns": 14784211625536,
    "event_type": "GoBlock",
    "goroutine_id": 8,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 10,
    "timestamp_ns": 14784211627776,
    "event_type": "GoBlock",
    "goroutine_id": 7,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 11,
    "timestamp_ns": 14784211646464,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 12,
    "timestamp_ns": 14784211650688,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 13,
    "timestamp_ns": 14784211658176,
    "event_type": "GoStart",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 14,
    "timestamp_ns": 14784211659328,
    "event_type": "GoBlock",
    "goroutine_id": 9,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 15,
    "timestamp_ns": 14784211663168,
    "event_type": "GoStart",
    "goroutine_id": 10,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 16,
    "timestamp_ns": 14784211678272,
    "event_type": "GoUnblock",
    "goroutine_id": 1,
    "goroutines": "... [TRUNCATED FOR LENGTH] ...",
    "channels": {},
    "mutexes": {}
  },
  {
    "event_id": 17,
    "timestamp_ns": 14784211701568,
    "event_type": "GoStart",
    "goroutine_id": 1,
    "goroutines": {
      "1": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "10": {
        "status": "running",
        "blocked_on": null,
        "locals_hint": "unknown"
      },
      "7": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "8": {
        "status": "blocked",
        "blocked_on": "chan receive",
        "locals_hint": "runtime.chanrecv1"
      },
      "9": {
        "status": "blocked",
        "blocked_on": "system goroutine wait",
        "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked.func1"
      }
    },
    "channels": {},
    "mutexes": {}
  }
]
</trace>

The current goroutine states are:
<current_state>
{
  "event_id": 17,
  "timestamp_ns": 14784211701568,
  "event_type": "GoStart",
  "goroutine_id": 1,
  "goroutines": {
    "1": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "10": {
      "status": "running",
      "blocked_on": null,
      "locals_hint": "unknown"
    },
    "7": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "8": {
      "status": "blocked",
      "blocked_on": "chan receive",
      "locals_hint": "runtime.chanrecv1"
    },
    "9": {
      "status": "blocked",
      "blocked_on": "system goroutine wait",
      "locals_hint": "runtime/trace.(*traceMultiplexer).startLocked.func1"
    }
  },
  "channels": {},
  "mutexes": {}
}
</current_state>

Predict the next scheduler event. What happens next?
Respond in JSON only — no markdown fences, no text outside the JSON object:
{"event_type":"GoStart|GoBlock|GoUnblock|GoCreate|GoEnd|GoSched","goroutine_id":<integer>,"reasoning":"<brief explanation>","confidence":"high|medium|low"}

[Assistant] {"event_type": "GoStart", "goroutine_id": 1}