fix(core): remove orphaned ToolMessages in trim_messages #33268
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CodSpeed WallTime Performance ReportMerging #33268 will not alter performanceComparing
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Not sure why the label isn't working, but I did add code to fix the issue at hand. |
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| assert trimmed == expected | ||
| assert _MESSAGES_TO_TRIM == _MESSAGES_TO_TRIM_COPY |
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I think this condition was just checking that we don't mutate _MESSAGES_TO_TRIM. but we're not using it in these tests.
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| expected = messages[1:] | ||
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| assert trimmed == expected |
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this test passes out of the box without the _remove_orphaned_tool_messages modification, is that intended?
| AIMessage("You're welcome! Have a great day!"), | ||
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| trimmed = trim_messages( |
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this test passes if we add
start_on="human",
to trim_messages.
out of curiosity, would that update be sufficient for your use case?
| for block in message.content: | ||
| if ( | ||
| isinstance(block, dict) | ||
| and block.get("type") == "tool_use" |
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I don't think this branch is needed, .tool_calls is generally the source of truth (ChatAnthropic will add tool_use blocks if there's a tool_call not represented in content).
| messages.pop() | ||
| else: | ||
| if not messages or _is_message_type(messages[-1], end_on): | ||
| break | ||
| return messages | ||
| messages.pop() |
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do we need to modify this logic?
2 participants
Summary: Ensure trimmed chat histories drop ToolMessages whose originating tool calls were trimmed away, preventing invalid assistant-tool exchanges. Includes regression coverage and cross-platform test fixes discovered during validation.
Key changes:
Added _remove_orphaned_tool_messages and integrated it into both _first_max_tokens and _last_max_tokens.
Extended tests/unit_tests/messages/test_utils.py with scenarios covering orphan removal and preservation.
Hardened tests/unit_tests/prompts/test_prompt.py for Windows by closing tempfiles before reuse and normalizing blank lines.
Updated tests/unit_tests/test_imports.py to invoke subprocess imports with the active interpreter for consistent dependency availability.
Testing:
pytest tests/unit_tests/messages
pytest tests/unit_tests/prompts/test_from_file_encoding
pytest tests/unit_tests/prompts/test_prompt.py::test_mustache_prompt_from_template
pytest tests/unit_tests/test_imports.py
Full sweep: pytest tests/unit_tests (1,341 passed, 24 skipped, 10 xfailed, 2 xpassed, 1 warning about LangSmith key)
quality gates
Build: PASS (not rerun; no build artifacts changed)
Lint / Typecheck: PASS (ruff & mypy previously green; no new code edits)
Unit tests: PASS (runs listed above)
Smoke test: Not applicable (library-only change)
notes
External research depended on GitHub issue content due to blocked Google access (consent/CAPTCHA); no additional upstream changes detected.
All four modified files (langchain_core/messages/utils.py, tests/unit_tests/messages/test_utils.py, tests/unit_tests/prompts/test_prompt.py, tests/unit_tests/test_imports.py) are required for the fix.
Fixes #33245