fix(stream): notify PartitionHub consumers on materializer shutdown#3347
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fix(stream): notify PartitionHub consumers on materializer shutdown#3347He-Pin wants to merge 3 commits into
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Motivation: When the materializer running a PartitionHub.sink is shut down (e.g. the hosting actor stops), consumers materialized on a different materializer may not be notified of the hub's termination. This mirrors the same bug in BroadcastHub (see #3345). Modification: Move registered-consumer notification from onUpstreamFailure to postStop so postStop is the single notification point. postStop now handles both Open (normal termination) and Closed (after upstream failure) states, ensuring registered consumers always receive the appropriate signal. Result: PartitionHub consumers are reliably notified when the hub's materializer shuts down, preventing consumers from hanging indefinitely. Tests: - sbt "stream-tests / Test / testOnly org.apache.pekko.stream.scaladsl.HubSpec" 51 passed, 0 failed References: Refs #3345
Motivation: If one consumer's callback throws during hub shutdown, the remaining consumers must still be notified. Modification: Wrap each callback.invoke in onUpstreamFailure and postStop with try/catch NonFatal so a single consumer failure does not short-circuit the notification loop. Result: All reachable consumers are notified even when one consumer's callback throws. Tests: - sbt "stream-tests / Test / testOnly org.apache.pekko.stream.scaladsl.HubSpec" 51 passed, 0 failed References: Refs #3345
Motivation: The Closed(_) branch comment in postStop said "fall through to notify registered below" but the code directly calls notifyRegisteredConsumers() rather than falling through, making the comment misleading. Modification: Reword the comment to accurately describe the direct call. Result: Comment now matches the actual control flow in postStop. Tests: - sbt "stream-tests / Test / testOnly org.apache.pekko.stream.scaladsl.HubSpec" — all 51 tests passed References: Refs #3345
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Motivation
When the materializer running a
PartitionHub.sinkis shut down (e.g. the hosting actor stops or crashes), consumers materialized on a different materializer may not be notified of the hub's termination. This mirrors the same bug pattern found inBroadcastHub(see #3345).Modification
onUpstreamFailuretopostStopso thatpostStopis the single notification point for all consumers.postStopnow handles bothOpen(normal termination) andClosed(after upstream failure) states, ensuring registered consumers always receive the appropriate signal.Before:
onUpstreamFailurenotified registered consumers directly, butpostStopdid not. This left a gap where consumers could miss notification during materializer shutdown.After:
postStopis the sole notification point for registered consumers, using the failure reason from theClosedstate when applicable.Result
PartitionHub consumers are reliably notified when the hub's materializer shuts down, preventing consumers from hanging indefinitely.
Tests
sbt "stream-tests / Test / testOnly org.apache.pekko.stream.scaladsl.HubSpec"— 51 passed, 0 failed"notify consumers when hub materializer is shut down"(PartitionHub section)References
Refs #3345