[jira] [Updated] (ZOOKEEPER-3010) Potential NPE in Observer#observeLeader and Follower#followLeader

["lujie (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ZOOKEEPER-3010?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

lujie updated ZOOKEEPER-3010:
-----------------------------
    Environment: 
 

 

  was:
 
{code:java}
static code analysis{code}
 

 


> 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:  
>  
>            Reporter: lujie
>            Priority: Major
>
> 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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