Fix race condition in SharedTsBlockQueue async listener causing NPE in MemoryPool.free() #17196
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When SharedTsBlockQueue.add() encounters memory pressure, it registers an
async listener on a MemoryReservationFuture to add the TsBlock later. If
the upstream FragmentInstance finishes and calls abort()/close() before the
listener executes, the following race occurs:
memory mapping
upstream FI's IDs, but the mapping no longer exists -> NPE
Fix: Check the
closedflag inside the async listener before adding theTsBlock. When closed, skip the add (memory was already freed by
abort/close) and complete channelBlocked to prevent hangs.
Also add a unit test that reproduces this race condition by using a
manually-controlled SettableFuture to simulate the blocked-on-memory path.