Fix task leaks in TaskScheduler shutdown#2677
Open
rintaro wants to merge 1 commit into
Open
Conversation
`shutDown` only cancels `currentlyExecutingTasks`, leaving `pendingTasks` untouched. External callers awaiting `waitToFinish()` on a pending task hang forever — `resultTask` keeps awaiting an `AsyncStream` that the scheduler will never yield into once `isShutDown` is set — and each such `QueuedTask` is leaked via the strong cycle through its `resultTask` closure. Cancel pending tasks too: `task.cancel()` cancels `resultTask`, the `for await` over the stream exits immediately on cancellation, and `waitToFinish()` returns in microseconds.
Member
Author
|
@swift-ci Please test |
Member
Author
|
@swift-ci Please test Windows |
hamishknight
approved these changes
May 29, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
shutDownonly canceledcurrentlyExecutingTasks, leavingpendingTasksuntouched.QueuedTaskwere leaked via theselfretain cycles in with theresultTaskclosure, and the task never completes itself.And possibly external callers awaiting
waitToFinish()on a pending task hang forever.Cancel pending tasks too:
task.cancel()cancelsresultTask, thefor awaitover the stream exits immediately on cancellation, andwaitToFinish()returns immediately.(In reality, I don't believe this affects anything because we only shutdown
SourceKitLSPServerwhen process exits)