Fix race condition in QueueSink causing async enumerable timeout#7973
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Aaronontheweb merged 2 commits intoakkadotnet:devfrom Dec 22, 2025
Aaronontheweb:claude-wt-AsyncEnumerableSpec.RunAsAsyncEnumerable_Throws_on_Abrupt_Stream_termination
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Fixed a timing-dependent race condition where RunAsAsyncEnumerable would timeout when the materializer shut down while a PullAsync() request was pending. The QueueSink.Logic.PostStop() method now properly completes any pending TaskCompletionSource stored in _currentRequest with a StreamDetachedException before shutting down, preventing orphaned Tasks that would never complete. This resolves intermittent test failures in AsyncEnumerableSpec.RunAsAsyncEnumerable_Throws_on_Abrupt_Stream_termination where the test would hang waiting for an exception that never arrived.
Aaronontheweb
commented
Dec 22, 2025
| public override void PostStop() | ||
| { | ||
| // Complete any pending request before shutting down to prevent orphaned Tasks | ||
| if (_currentRequest.HasValue) |
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Need to do this otherwise the IAsyncEnumerable hangs on the _currentRequest value
…rable_Throws_on_Abrupt_Stream_termination
Arkatufus
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Jan 7, 2026
…adotnet#7973) Fixed a timing-dependent race condition where RunAsAsyncEnumerable would timeout when the materializer shut down while a PullAsync() request was pending. The QueueSink.Logic.PostStop() method now properly completes any pending TaskCompletionSource stored in _currentRequest with a StreamDetachedException before shutting down, preventing orphaned Tasks that would never complete. This resolves intermittent test failures in AsyncEnumerableSpec.RunAsAsyncEnumerable_Throws_on_Abrupt_Stream_termination where the test would hang waiting for an exception that never arrived.
Aaronontheweb
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that referenced
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Jan 8, 2026
Fixed a timing-dependent race condition where RunAsAsyncEnumerable would timeout when the materializer shut down while a PullAsync() request was pending. The QueueSink.Logic.PostStop() method now properly completes any pending TaskCompletionSource stored in _currentRequest with a StreamDetachedException before shutting down, preventing orphaned Tasks that would never complete. This resolves intermittent test failures in AsyncEnumerableSpec.RunAsAsyncEnumerable_Throws_on_Abrupt_Stream_termination where the test would hang waiting for an exception that never arrived.
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Summary
Fixed a timing-dependent race condition where
RunAsAsyncEnumerablewould timeout when the materializer shut down while aPullAsync()request was pending.Changes
QueueSink.Logic.PostStop()to properly complete any pendingTaskCompletionSourcestored in_currentRequestwith aStreamDetachedExceptionbefore shutting downIssue
This resolves intermittent test failures in
AsyncEnumerableSpec.RunAsAsyncEnumerable_Throws_on_Abrupt_Stream_terminationwhere the test would hang waiting for an exception that never arrived.Root Cause
When the materializer shut down abruptly, the
PostStop()method only set up a callback handler for future pull requests but didn't clean up already-pending requests waiting for data. The pendingTaskCompletionSourcein_currentRequestwould remain incomplete, causing the async enumerable to hang indefinitely.Testing