GitHub user afine opened a pull request:
https://github.com/apache/zookeeper/pull/280
ZOOKEEPER-2806: Flaky test:
org.apache.zookeeper.server.quorum.FLEBackwardElectionRoundTest.testBackwardElectionRound
Here is an example of a test failure:
https://builds.apache.org/job/ZooKeeper_branch34_jdk8/1016/testReport/org.apache.zookeeper.server.quorum/FLEBackwardElectionRoundTest/testBackwardElectionRound/
This flaky test is caused by the reuse of a `ByteBuffer` object between
`QuorumCnxManager`s.
When sending a `ByteBuffer` we reset its position first:
```
synchronized void send(ByteBuffer b) throws IOException {
byte[] msgBytes = new byte[b.capacity()];
try {
b.position(0);
b.get(msgBytes);
} catch (BufferUnderflowException be) {
LOG.error("BufferUnderflowException ", be);
return;
}
dout.writeInt(b.capacity());
dout.write(b.array());
dout.flush();
}
```
`b.get(msgBytes);` changes the position of the `ByteBuffer`. So we can have
a race here that results in a `BufferUnderflowException` causing a message
never to be sent and this test to fail.
The fix is to create a new `ByteBuffer` for each message we send in the
test.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/afine/zookeeper ZOOKEEPER-2806
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/zookeeper/pull/280.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #280
----
commit 384bf271a79333a7d646a74e1e6c326955d7001c
Author: Abraham Fine <[email protected]>
Date: 2017-06-13T18:46:48Z
ZOOKEEPER-2806: Flaky test:
org.apache.zookeeper.server.quorum.FLEBackwardElectionRoundTest.testBackwardElectionRound
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