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[util] Shut down scheduled executor in Wait.poll to fix thread leak - #4955
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Wait.poll created a single-thread ScheduledExecutorService but never shut it down. The default thread factory produces non-daemon threads, so every poll() call left a lingering worker thread alive after returning, leaking a thread (and preventing clean JVM shutdown) on each invocation. Shut the executor down in a finally block so it is released on every exit path, preserving all existing return values. Adds a regression test that fails before and passes after the fix.
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: brendandburns, yue9944882 The full list of commands accepted by this bot can be found here. The pull request process is described here DetailsNeeds approval from an approver in each of these files:
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What type of PR is this?
/kind bug
Bug
io.kubernetes.client.util.wait.Wait#pollcreates a single-threadScheduledExecutorServicebut never shuts it down. The default thread factory produces non-daemon threads, so everypoll()call leaves a lingering worker thread alive after the method returns. This leaks a thread on each invocation and can prevent clean JVM shutdown.future.cancel(true)only stops the scheduled task; it does not release the executor's worker thread.Fix
Shut the executor down in a
finallyblock so it is released on every exit path (loop success, exception, and timeout). All existing return values are preserved — the change is behavior-preserving except for releasing the leaked thread.Verification
Added a focused regression test
WaitTest#pollShutsDownExecutorThreadAfterReturningthat captures the executor thread the condition runs on and asserts it has terminated afterpollreturns.Tests run: 1, Failures: 1(worker thread stays alive)Tests run: 1, Failures: 0Ran:
./mvnw -pl util -am -Dtest=WaitTest -Dsurefire.failIfNoSpecifiedTests=false test