fix: Handle LLM refusal responses to prevent NoneType errors#1799
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pk-zipstack wants to merge 1 commit intomainfrom
Open
fix: Handle LLM refusal responses to prevent NoneType errors#1799pk-zipstack wants to merge 1 commit intomainfrom
pk-zipstack wants to merge 1 commit intomainfrom
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When Anthropic (or other providers) refuse to generate a response due to safety restrictions, LiteLLM returns content=None with finish_reason="refusal". Previously, this caused a crash in _post_process_response when calling .find() on None, producing the unhelpful error: "'NoneType' object has no attribute 'find'". Now detect None content early in complete(), acomplete(), and stream_complete(), check finish_reason, and raise a descriptive LLMError that clearly indicates the refusal or empty response cause. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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SDK1 Tests - Full Report
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pk-zipstack
requested review from
Deepak-Kesavan,
chandrasekharan-zipstack and
hari-kuriakose
chandrasekharan-zipstack
approved these changes
Feb 19, 2026
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What
stop_reason: "refusal") in SDK1'sLLM.complete(),acomplete(), andstream_complete()methods.LLMErrorinstead of crashing with'NoneType' object has no attribute 'find'.Why
content=Nonewithfinish_reason="refusal". The SDK did not check forNonecontent before passing it to_post_process_response(), which called.find()onNone."Error from LLM provider 'anthropic': 'NoneType' object has no attribute 'find'"— making it very hard to diagnose the actual issue (a safety refusal).How
llm.py—complete()andacomplete(): After extractingresponse_textfrom the LiteLLM response, check if it'sNone. If so, inspectfinish_reasonand raiseLLMErrorwith a clear message.llm.py—stream_complete(): Extracted chunk processing into_process_stream_chunk()helper. Checksfinish_reasonon each chunk for refusal.llm.py—_raise_for_empty_response(): New helper method that raisesLLMErrorwith status 400 for refusals, 500 for other empty responses.common.py—LLMResponseCompat: Hardened__str__()and__repr__()to handleNonetext without crashing.Before:
"Error from LLM provider 'anthropic': 'NoneType' object has no attribute 'find'"After:
"The LLM refused to generate a response due to safety restrictions. Please review your prompt and try again."Can this PR break any existing features. If yes, please list possible items. If no, please explain why. (PS: Admins do not merge the PR without this section filled)
Nonecontent before existing processing logic runs. Normal responses (wherecontentis a string) are completely unaffected — the new check is skipped. The only behavioral change is that refusal/empty responses now raise a descriptiveLLMErrorinstead of an opaqueAttributeError.Database Migrations
Env Config
Relevant Docs
stop_reason: "refusal""refusal"through asfinish_reasonRelated Issues or PRs
Dependencies Versions
Notes on Testing
content=None,finish_reason="refusal"), empty responses, and normal responses. All 13 new tests pass alongside the existing 70 SDK1 tests (83 total).Checklist
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