Update 1.11.1 from 1.9.2 logs of docker-api-1 has error:Failed to generate name after answer, use query instead

[aijuntao]

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Dify version

1.11.1

Cloud or Self Hosted

Self Hosted (Docker)

Steps to reproduce

Update 1.11.1 from 1.9.2 logs of docker-api-1 has error:

2025-12-14 12:26:42.609 ERROR [Thread-99 (_generate_conversation_name_worker)] [llm_generator.py:82] - Failed to generate name after answer, use query instead
Traceback (most recent call last):
File "/app/api/core/llm_generator/llm_generator.py", line 79, in generate_conversation_name
result_dict = json.loads(cleaned_answer)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/json/init.py", line 346, in loads
return _default_decoder.decode(s)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/json/decoder.py", line 338, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/json/decoder.py", line 356, in raw_decode
raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)
2025-12-14 12:26:42.691 ERROR [Thread-183 (_generate_conversation_name_worker)] [llm_generator.py:82] - Failed to generate name after answer, use query instead
Traceback (most recent call last):
File "/app/api/core/llm_generator/llm_generator.py", line 79, in generate_conversation_name
result_dict = json.loads(cleaned_answer)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/json/init.py", line 346, in loads
return _default_decoder.decode(s)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/json/decoder.py", line 338, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/json/decoder.py", line 356, in raw_decode
raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

✔️ Expected Behavior

fix it

❌ Actual Behavior

No response

[dosubot]

The error happens because the code tries to parse an empty or invalid JSON string when generating conversation names. In the current implementation, if the LLM response doesn't contain a valid JSON object, json.loads(cleaned_answer) raises a JSONDecodeError, which is caught and logged, and then the original query is used as the conversation name. However, the exception still appears in your logs because there's no pre-check for empty or whitespace-only strings before attempting to parse them.

To reduce noise in your logs and handle this more gracefully, you can add a check before calling json.loads(cleaned_answer). For example:

if not cleaned_answer or not cleaned_answer.strip():
    answer = query
else:
    try:
        result_dict = json.loads(cleaned_answer)
        answer = result_dict["Your Output"]
    except json.JSONDecodeError:
        logger.exception("Failed to generate name after answer, use query instead")
        answer = query

This way, empty or whitespace-only responses won't trigger a JSONDecodeError, and you'll avoid unnecessary error logs. The fallback to the query as the conversation name is already the intended behavior if name generation fails, as confirmed by the unit tests and current logic. No recent pull requests directly address this, so a small patch like the above should resolve the issue for now.
You can see the relevant code and logic here.

To reply, just mention @dosu.

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[tysoncung]

I noticed this issue. Have you tried checking the error logs or console output? That might help narrow down the root cause. I'd be happy to help investigate if you can share more details about your environment (OS, version, etc.).