fix(tasks): prevent duplicate dispatch on all-runners-busy requeue#3988
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fix(tasks): prevent duplicate dispatch on all-runners-busy requeue#3988cursor[bot] wants to merge 1 commit into
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When every runner is at capacity, ErrAllRunnersBusy requeued tasks by enqueueing them while they still sat in the running set, then sending EventTypeRequeued from a defer. A periodic queue tick could ClaimAndDequeue the task in that window and start a second dispatch on the same TaskRunner. Release running/active bookkeeping before enqueueing and notify the pool synchronously, matching the reconciler requeue paths. Co-authored-by: Denis Gukov <fiftin@outlook.com>
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Bug and impact
When all remote runners are busy, a task is requeued via
ErrAllRunnersBusy. The old path enqueued the task while it still remained in the pool's running set, and only sentEventTypeRequeuedfrom adeferafterrun()returned.A periodic queue tick (
EventTypeEmpty, every 5s) or any other queue event could run in that window,ClaimAndDequeuethe task, and start a second dispatch on the sameTaskRunner. That can cause duplicate runner assignments, corrupted pool state, and duplicate task execution.Root cause
TaskRunner.run()usedEnqueue()immediately but deferredEventTypeRequeued(which callsonTaskStop()). The reconciler'srequeueTaskRunnerOffline()already documented the correct pattern but only sent the event synchronously — it still enqueued before releasing running state.Fix
onTaskStop()beforeEnqueue()so the task is never simultaneously queued and running.EventTypeRequeuedsynchronously (not fromdefer) so the current queue pass skips an immediate retry.Validation
TestTaskRunner_ErrAllRunnersBusy_ReleasesRunningBeforeEnqueueTestTaskPool_RequeuedEventCleansRunningStateAndSkipsImmediateRetryand reconciler requeue tests pass