Currently when we identify version probing we return early from onAssignment and never get to updating the TaskManager and general state with the new assignment. Since we do actually give out "real" assignments even during version probing, a StreamThread should take real ownership of its tasks/partitions including cleaning them up in onPartitionsRevoked which gets invoked when we call onLeavePrepare as part of triggering the follow-up rebalance.
Every member will always get an assignment encoded with the lowest common version, so there should be no problem decoding a VP assignment. We should just allow onAssignment to proceed as usual so that the TaskManager is in a consistent state, and knows what all its tasks/partitions are when the first rebalance completes and the next one is triggered.
Reviewers: Boyang Chen <boyang@confluent.io>, Matthias J. Sax <mjsax@apache.org>, Guozhang Wang <wangguoz@gmail.com>
A. Sophie Blee-Goldman