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LangChain

2026 · Open source · Merged contributor

LangChain is an agent engineering platform (144,000+ stars). I fixed chain-group tracing so asyncio cancellation and other BaseException interrupts still call on_chain_error instead of leaving the LangSmith run pending.

Contributions

  • Caught BaseException in trace_as_chain_group and atrace_as_chain_group, matching other core usage.
  • Still invoke on_chain_error, then re-raise so cancellation is not swallowed.
  • Added unit tests covering cancelled chain-group traces.

Outcomes

  • Core tracing fix merged upstream into langchain-ai/langchain.
  • Cancelled or interrupted chain groups now mark the run as errored instead of pending.