fix(langgraph): handle CancelledError in AsyncBackgroundExecutor cleanup#6974
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weiguang li (OiPunk) wants to merge 1 commit intolangchain-ai:mainfrom
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In Python 3.11+, CancelledError inherits BaseException and can propagate into asyncio.wait's internal waiter when the parent task is cancelled during AsyncPregelLoop.__aexit__, causing random crashes in production. Wrap asyncio.wait in try/except to gracefully handle cancellation during cleanup: cancel remaining background tasks and skip exception checks for tasks that haven't completed yet. fixes langchain-ai#6950 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
CancelledErrorinAsyncBackgroundExecutor.__aexit__to prevent random crashes duringastreamcleanupCancelledErrorinheritsBaseExceptionand propagates intoasyncio.wait's internal waiter when the parent task is cancelled, breaking the cleanup flowasyncio.wait(tasks)in try/except: on cancellation, cancel remaining background tasks to avoid orphaned coroutinesInvalidStateError)fixes #6950
Changes
libs/langgraph/langgraph/pregel/_executor.py: AddedCancelledErrorhandling in__aexit__, plus atask.done()guard before checking task exceptionslibs/langgraph/tests/test_executor_async.py: 5 new unit tests covering cancellation during cleanup, normal exit, task exceptions, and cancel-on-exit behaviorTest plan
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