Explicitly check for None rather than False
#1240
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If the group leader somehow gets in a state that it has an empty partition assignment, then `self._assignment_snapshot` will be `{}` which evaluates to `False`. So `self._subscription.mark_for_reassignment()` will never be triggered, even if `self._assignment_snapshot != self._metadata_snapshot`.
Fixes the symptoms of #1237 although I suspect there's an additional bug in that case that triggers the condition of the the group leader getting an empty partition assignment.
This was referenced Oct 6, 2017
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Discussed in person with @dpkp and he agreed it should be merged. |
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If the group leader somehow gets in a state that it has an empty partition assignment, then
self._assignment_snapshotwill be{}which evaluates toFalse. Soself._subscription.mark_for_reassignment()will never be triggered, even ifself._assignment_snapshot != self._metadata_snapshot.Here is the relevant upstream Java code:
https://github.com/apache/kafka/blob/c5d26c4829583c95af7ca9e961a4d3954f8e09eb/clients/src/main/java/org/apache/kafka/clients/consumer/internals/ConsumerCoordinator.java#L197
Fixes the symptoms of #1237 although I suspect there's an additional bug in that case that triggers the condition of the the group leader getting an empty partition assignment.
I'm hesitant with this fix because I still don't fully understand the race condition that results in the group leader simultaneously having:
3.
subscription.needs_partition_assignment = False.Related: #1237 / #1241 / #1242