[GitHub] zookeeper issue #229: ZOOKEEPER-2759: Flaky test: org.apache.zookeeper.serve...

[hanm <gi...@git.apache.org>]

Github user hanm commented on the issue:

    https://github.com/apache/zookeeper/pull/229
  
    Thanks for work on this! I hope we have more contributors focus on improving the test.
    
    The proposed fix masks the real problem - it will always success no matter what - even if the connection was succeeded, since the halt will clean up the sender worker map of the peer 0.
    
    >>  a race condition between the removal of the relevant sid from senderWorkerMap for peer0 and the 3 second delay from assertEventuallyNotConnected.
    I think there is a race, but my observation on it is slightly different. The race is between when peer 0 received (and finished) establish connection with peer 1, and the assert inside assertEventuallyNotConnected.
    
    >> may not destroy them in time for the test assertion.
    Because of the race, once peer 0 has received the connection, its sender worker map will has sid 1 entry forever until the death of the peer 0 itself. 
    
    I think instead of checking on peer 0, we can check peer 1. Its sender worker map should always be clean. We can't check peer 0 here because the current API does not encode the true state of the connection - it only encodes what happened (the connection from 1 to 0 was established on 0's side), but it does not encode the status of the connection (is the connection still alive or not - in this case peer 1 will close the socket later when it found out peer 0 has no auth. but on peer 0 side the sender work will have sid 1 inside until its death, what's done has been done.). The state of peer 1 wrt its sender map should also reflect state of peer 0  since there is only a single connection between 0 and 1.
    
    Something like this should serve the purpose:
    assertEventuallyNotConnected(peer1, 0);
    
    Maybe add a sleep before it to make sure all the connection attempts were made (from 0  to 1 and from 1 to 0 two ways), but it's a best effort. 5 sec sounds enough.
    



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