{"record":{"id":"b57417feb62beee0","repo":"mudler/LocalAI","slug":"syntax-error-in-inline-reward-function-name","errorCode":null,"errorMessage":"Syntax error in inline reward function '{name}': {e}","messagePattern":"Syntax error in inline reward function '(.+?)': (.+?)","errorType":"validation","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"backend/python/trl/reward_functions.py","lineNumber":171,"sourceCode":"    Available modules: re, math, json, string.\n    \"\"\"\n    func_source = (\n        f\"def _user_reward_{name}(completions, **kwargs):\\n\"\n        + \"\\n\".join(f\"    {line}\" for line in code.splitlines())\n    )\n\n    restricted_globals = {\n        \"__builtins__\": _SAFE_BUILTINS,\n        \"re\": re,\n        \"math\": math,\n        \"json\": json,\n        \"string\": string,\n    }\n\n    try:\n        compiled = compile(func_source, f\"<inline-reward-{name}>\", \"exec\")\n    except SyntaxError as e:\n        raise ValueError(f\"Syntax error in inline reward function '{name}': {e}\")\n\n    exec(compiled, restricted_globals)\n    func = restricted_globals[f\"_user_reward_{name}\"]\n\n    # Validate with a quick smoke test\n    try:\n        result = func([\"test\"], answer=[\"test\"])\n        if not isinstance(result, list):\n            raise ValueError(\n                f\"Inline reward function '{name}' must return a list, got {type(result).__name__}\"\n            )\n    except Exception as e:\n        if \"must return a list\" in str(e):\n            raise\n        # Other errors during smoke test are acceptable (e.g. missing kwargs)\n        pass\n\n    return func","sourceCodeStart":153,"sourceCodeEnd":189,"githubUrl":"https://github.com/mudler/LocalAI/blob/44413a9d06bf5bc52ce088ba8ca74e5a2e8bee26/backend/python/trl/reward_functions.py#L153-L189","documentation":"compile_inline_reward takes user-supplied Python source defining a function named _user_reward_<name> and runs compile() on it before exec'ing in a restricted namespace. A SyntaxError from compile() is re-raised as ValueError with the offending function name and compiler message, so the caller knows which spec failed.","triggerScenarios":"An inline reward spec whose code has a missing colon/indent, uses print without import under Python 2 habits, or was truncated by shell quoting/JSON escaping (e.g. lost newlines).","commonSituations":"Passing code through multiple JSON layers that eat backslash-n; writing the function body without the required def _user_reward_<name>() signature mismatch causing parse errors; copy-paste from notebooks with smart quotes.","solutions":["Reproduce locally: python -c \"compile(open('reward.py').read(), 'x', 'exec')\" to find the exact line.","Fix the syntax and ensure the code defines _user_reward_<name> exactly (the compile step also expects that symbol to exist afterwards).","Check the JSON encoding of the code string — real newlines must survive as \\n in the JSON payload."],"exampleFix":"# before\ncode = \"def _user_reward_len(c, **kw) return [float(len(x)) for x in c]\"  # missing colon\n# after\ncode = \"def _user_reward_len(c, **kw):\\n    return [float(len(x)) for x in c]\"","handlingStrategy":"validation","validationCode":"def reward_code_compiles(name: str, code: str) -> bool:\n    try:\n        compile(code, f\"<inline-reward-{name}>\", \"exec\")\n        return True\n    except SyntaxError:\n        return False","typeGuard":null,"tryCatchPattern":"try:\n    func = compile_inline_reward(name, code)\nexcept ValueError as e:\n    if \"Syntax error\" in str(e):\n        return validation_error(field=\"reward_funcs\", detail=str(e))\n    raise","preventionTips":["compile() the code client-side before sending the request.","Store reward snippets as .py files in tests so editors catch syntax errors.","Round-trip the code through json.loads(json.dumps(code)) to verify escaping."],"tags":["trl","reward-functions","inline-code","syntax-error","localai"],"backgroundTag":null,"analyzedSha":"44413a9d06bf5bc52ce088ba8ca74e5a2e8bee26","analyzedAt":"2026-08-15T10:13:50.291Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}