There is this paper presented recently that discusses some simple bugs in Apache projects, including ZooKeeper:
https://www.usenix.org/conference/osdi14/technical-sessions/presentation/yuan Apparently the authors proposed fixes for the ZK bugs they found in ZOOKEEPER-1881. My sense is that the fixes are minor and some of them not entirely necessary, but please have a look yourself and draw your own conclusions. In any case, it is great to have contributions that help us improve our code. -Flavio
