FlinkPravegaWriter cannot be flushed following a write error

[EronWright]

Problem description
When close or flush is called after a write that has failed internally, the method will stall forever.

Problem location
The problem is due to bad accounting of pending writes based on pendingWritesCount. The flush method waits for the count to reach zero, but the count is not properly decremented on error. (ref)

Suggestions for an improvement
Decrement the write count irrespective of success or failure.

[fpj]

Why is the write failing? Could you post the error?

[EronWright]

@fpj I hit the problem while developing a unit test for the writer. I don't think the specific error is significant. Take a look at the referenced code block, observing that the pendingWritesCount is not decremented on error, causing a subsequent flush to wait forever for pendingWritesCount to reach zero.