lujie created ZOOKEEPER-3010:
--------------------------------
Summary: Potential NPE in Observer#observeLeader and
Follower#followLeader
Key: ZOOKEEPER-3010
URL: https://issues.apache.org/jira/browse/ZOOKEEPER-3010
Project: ZooKeeper
Issue Type: Bug
Affects Versions: 3.6.0
Environment:
{code:java}
static code analysis{code}
Reporter: lujie
After ZK-3006 , I develop a very simple static analysis tool to find other
Potential NPE like ZK-3006, this bug is found by this tool and carefully
studied by myself, hopefully someone can confirm it.
h2. Bug description:
callee Learner#findLeader will return null and callee developer check it but
just log:
{code:java}
// code placeholder
if (leaderServer == null) {
LOG.warn("Couldn't find the leader with id = " + current.getId());
}
return leaderServer;
{code}
caller Observer#observeLeader and Follower#followLeader will directly use
return value w/o null check:
{code:java}
//Follower#followLeader
QuorumServer leaderServer = findLeader();
try {
connectToLeader(leaderServer.addr, leaderServer.hostname);
..........
}
//Observer#observeLeader
QuorumServer leaderServer = findLeader();
LOG.info("Observing " + leaderServer.addr);
try {
connectToLeader(leaderServer.addr, leaderServer.hostname);
}{code}
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