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e7e4100 e649070 e7e4100 e649070 e7e4100 e649070 e7e4100 e649070 e7e4100 e649070 e7e4100 e649070 e7e4100 492315e e7e4100 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 | """Deterministic property-based fuzzer for the fixed Qwen chat templates.
Generates structurally valid conversations (system merging, multipart vision
content, tool loops with mixed argument shapes, explicit and in-content
reasoning, planted error payloads) and asserts nine invariants:
1. render Rendering never raises on valid input.
2. parity chat_template.jinja and chat_template_oneline.txt render
byte-identically.
3. balance <|im_start|> and <|im_end|> counts match
(add_generation_prompt=False).
4. content Planted user text, assistant answers, and (when preserved)
reasoning appear verbatim in the output.
5. xml-fidelity In XML mode every mapping tool-argument key appears as
<parameter=key>; values appear verbatim when truncation
is disabled.
6. json-validity In JSON mode every emitted <tool_call> body parses as JSON.
7. warning The tool-error warning appears iff an error payload was
planted (no false positives, no false negatives).
8. prefix render(messages[:k]) is a strict prefix of
render(messages[:k+1]) at every generation boundary under
default preserve_thinking. Prefixes that split a merged
system block or a consecutive tool-result batch are
skipped: those intermediate states are never rendered in
real serving, where the model generates only after the
full tool-result batch is appended.
9. prefill enable_thinking=False ends the generation prompt with the
empty think prefill.
Usage:
python3 scripts/fuzz_template.py [--cases 500] [--seed 0] [--template chat_template.jinja]
Exits nonzero on any invariant failure and prints a JSON repro for each.
"""
import argparse
import json
import os
import random
import sys
import traceback
from jinja2 import Environment, FileSystemLoader, StrictUndefined
# Alphabet deliberately excludes every error-detector keyword, control-tag
# fragment, and special-token prefix so invariant 7 stays two-sided.
WORDS = ['alpha', 'bravo', 'delta', 'gamma', 'lumen', 'quartz', 'river',
'stone', 'matrix', 'vector', 'naïve', 'café', '数据', '結果']
def _phrase(rnd, lo=2, hi=5):
sep = '\n' if rnd.random() < 0.1 else ' '
return sep.join(rnd.choice(WORDS) + str(rnd.randint(0, 99))
for _ in range(rnd.randint(lo, hi)))
def _gen_case(rnd):
kwargs = {}
fmt = 'json' if rnd.random() < 0.3 else 'xml'
if fmt == 'json':
kwargs['tool_call_format'] = 'json'
if rnd.random() < 0.3:
kwargs['reasoning_effort'] = rnd.choice(['low', 'medium', 'high', 'xhigh'])
no_think = rnd.random() < 0.15
if no_think:
kwargs['enable_thinking'] = False
preserve = True
if rnd.random() < 0.2:
kwargs['preserve_thinking'] = False
preserve = False
if rnd.random() < 0.2:
kwargs['add_vision_id'] = True
trunc_args = False
if fmt == 'xml' and rnd.random() < 0.2:
kwargs['max_tool_arg_chars'] = rnd.choice([8, 40])
trunc_args = True
if fmt == 'xml' and rnd.random() < 0.15:
kwargs['max_tool_response_chars'] = 80
msgs = []
user_texts, answers, reasonings, xml_keys, xml_vals = [], [], [], [], []
planted_error = False
for _ in range(rnd.randint(0, 2)):
msgs.append({'role': 'system', 'content': _phrase(rnd)})
for _ in range(rnd.randint(1, 3)):
text = _phrase(rnd)
if rnd.random() < 0.25:
parts = [{'type': 'image', 'image': 'x'}
for _ in range(rnd.randint(1, 2))]
parts.append({'type': 'text', 'text': text})
msgs.append({'role': 'user', 'content': parts})
else:
msgs.append({'role': 'user', 'content': text})
user_texts.append(text)
for _ in range(rnd.randint(0, 2)):
calls = []
for c in range(rnd.randint(1, 2)):
roll = rnd.random()
if roll < 0.5:
value = _phrase(rnd)
args = {'k%d' % c: value}
xml_keys.append('k%d' % c)
if fmt == 'xml' and not trunc_args:
xml_vals.append(value)
elif roll < 0.7:
args = json.dumps({'q': _phrase(rnd)})
elif roll < 0.8:
args = rnd.randint(0, 999)
elif roll < 0.9:
args = [1, 2, 3]
else:
args = {}
fn = {'name': 'fn%d' % c, 'arguments': args}
calls.append({'type': 'function', 'function': fn}
if rnd.random() < 0.5 else dict(fn))
amsg = {'role': 'assistant',
'content': _phrase(rnd) if rnd.random() < 0.4 else '',
'tool_calls': calls}
if rnd.random() < 0.5:
rz = _phrase(rnd)
r_pick = rnd.random()
if r_pick < 0.34:
amsg['content'] = '<think>\n' + rz + '\n</think>\n\n' + amsg['content']
elif r_pick < 0.67:
amsg['reasoning_content'] = rz
else:
amsg['reasoning'] = rz
if preserve:
reasonings.append(rz)
msgs.append(amsg)
for _ in calls:
if rnd.random() < 0.12:
msgs.append({'role': 'tool', 'content': '{"error": "boom"}'})
planted_error = True
else:
msgs.append({'role': 'tool', 'content': 'result ' + _phrase(rnd)})
ans = _phrase(rnd)
amsg = {'role': 'assistant', 'content': ans}
if rnd.random() < 0.6:
rz = _phrase(rnd)
r_pick = rnd.random()
if r_pick < 0.34:
amsg['content'] = '<think>\n' + rz + '\n</think>\n\n' + ans
elif r_pick < 0.67:
amsg['reasoning_content'] = rz
else:
amsg['reasoning'] = rz
if preserve:
reasonings.append(rz)
msgs.append(amsg)
answers.append(ans)
return dict(msgs=msgs, kwargs=kwargs, fmt=fmt, preserve=preserve,
no_think=no_think, user_texts=user_texts, answers=answers,
reasonings=reasonings, xml_keys=xml_keys, xml_vals=xml_vals,
planted_error=planted_error)
def _check(case, tpl, other, failures, idx):
msgs, kw = case['msgs'], case['kwargs']
def fail(inv, detail):
failures.append({
'case': idx, 'invariant': inv, 'detail': detail,
'repro': json.dumps({'messages': msgs, 'kwargs': kw},
ensure_ascii=False, default=str)})
try:
out = tpl.render(messages=msgs, add_generation_prompt=False, **kw)
except Exception:
fail('render', traceback.format_exc().strip().splitlines()[-1])
return
try:
out_b = other.render(messages=msgs, add_generation_prompt=False, **kw)
if out != out_b:
i = next((j for j in range(min(len(out), len(out_b)))
if out[j] != out_b[j]), min(len(out), len(out_b)))
fail('parity', 'first diff at char %d: %r vs %r'
% (i, out[i:i + 40], out_b[i:i + 40]))
except Exception:
fail('parity', traceback.format_exc().strip().splitlines()[-1])
if out.count('<|im_start|>') != out.count('<|im_end|>'):
fail('balance', '%d starts vs %d ends'
% (out.count('<|im_start|>'), out.count('<|im_end|>')))
for text in case['user_texts'] + case['answers'] + case['reasonings']:
if text not in out:
fail('content', 'missing %r' % text[:60])
break
if case['fmt'] == 'xml':
for key in case['xml_keys']:
if ('<parameter=%s>' % key) not in out:
fail('xml-fidelity', 'missing key %s' % key)
break
for value in case['xml_vals']:
if value not in out:
fail('xml-fidelity', 'missing value %r' % value[:60])
break
if case['fmt'] == 'json':
for block in out.split('<tool_call>\n')[1:]:
body = block.split('\n</tool_call>')[0]
try:
json.loads(body)
except Exception:
fail('json-validity', body[:80])
break
warned = '⚠️ SYSTEM WARNING' in out
if warned != case['planted_error']:
fail('warning', 'warned=%s planted=%s' % (warned, case['planted_error']))
if case['preserve']:
prev = None
for k in range(1, len(msgs) + 1):
if k < len(msgs) and msgs[k]['role'] == msgs[k - 1]['role'] \
and msgs[k]['role'] in ('system', 'tool'):
continue
cur = tpl.render(messages=msgs[:k], add_generation_prompt=False, **kw)
if k > 1 and msgs[k - 1].get('role') == 'assistant':
prompt = tpl.render(messages=msgs[:k - 1], add_generation_prompt=True, **kw)
if not cur.startswith(prompt):
if prompt.endswith('<think>\n\n</think>\n\n') and cur.startswith(prompt[:-11]):
# Fuzzer randomly injected reasoning into a non-thinking turn. KV cache naturally breaks here.
pass
else:
fail('prefix', 'generation prompt at turn %d not prefix of history at turn %d' % (k - 1, k))
break
if prev is not None and not cur.startswith(prev):
fail('prefix', 'history mutated at turn %d' % k)
break
prev = cur
if case['no_think']:
gen = tpl.render(messages=msgs, add_generation_prompt=True, **kw)
if not gen.endswith('<think>\n\n</think>\n\n'):
fail('prefill', repr(gen[-40:]))
def run_fuzz(cases=500, seed=0, template_dir=None,
template_file='chat_template.jinja', max_failures=10):
template_dir = template_dir or os.path.dirname(
os.path.dirname(os.path.abspath(__file__)))
env = Environment(loader=FileSystemLoader(template_dir),
undefined=StrictUndefined, keep_trailing_newline=True,
lstrip_blocks=True, trim_blocks=True)
env.globals['raise_exception'] = \
lambda m: (_ for _ in ()).throw(Exception(m))
tpl = env.get_template(template_file)
other_name = ('chat_template.jinja'
if template_file == 'chat_template_oneline.txt'
else 'chat_template_oneline.txt')
other = env.get_template(other_name)
rnd = random.Random(seed)
failures = []
for i in range(cases):
_check(_gen_case(rnd), tpl, other, failures, i)
if len(failures) >= max_failures:
break
return failures
def main():
parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
parser.add_argument('--cases', type=int, default=500)
parser.add_argument('--seed', type=int, default=0)
parser.add_argument('--template', default='chat_template.jinja')
args = parser.parse_args()
failures = run_fuzz(cases=args.cases, seed=args.seed,
template_file=args.template)
if failures:
for f in failures:
print('FAIL case %d [%s]: %s' % (f['case'], f['invariant'], f['detail']))
print(' repro: %s' % f['repro'][:800])
print('\n%d invariant violation(s) in %d cases (seed %d)'
% (len(failures), args.cases, args.seed))
sys.exit(1)
print('All invariants held over %d generated conversations (seed %d).'
% (args.cases, args.seed))
if __name__ == '__main__':
main()
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