Fix NPE in WorkerState.transferLocalBatch causing worker crashes#8896
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Restores the 1.x "unknown task -> drop + warn" guard lost in the STORM-2306 messaging redesign. Adds WorkerStateTest to verify no NPE is thrown when a tuple addressed to an unknown task is received.
rzo1
approved these changes
Jul 9, 2026
reiabreu
approved these changes
Jul 11, 2026
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Thanks for the fix @dpol1 |
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Summary
Fixes #7533 — NPE in
WorkerState.transferLocalBatchcausing workers to exit.Root cause
transferLocalBatchlooks uptaskToExecutorQueue.get(tuple.dest)and dereferences the result without a null check. The map contains only tasks assigned to this worker at startup. During a rebalance, peer workers with a stale assignment cache send tuples to tasks this worker no longer owns; the lookup returnsnulland the NPE propagates toStormServerHandler.exceptionCaught, which callsRuntime.getRuntime().exit(1).This is a regression from STORM-2306: the 1.x
transferLocalpath guarded both lookups explicitly ("Received invalid messages for unknown tasks. Dropping…"). The redesign dropped both guards.Changes
WorkerState.java: null check onqueueafter line 572; onnull, drop the tuple, log a warning withtuple.dest, incrementdropCount. Method visibilityprivate→ package-private for testability.WorkerStateTest.java: new test verifying that a tuple addressed to an unknown task is silently dropped (no exception thrown).