tree c087f41d7da1dd3f392b538632d54a6e93965cae
parent 3dc4ddf2575299aad2c93abce02e8ca0f5d9256b
author Rajan Dhabalia <rdhabalia@apache.org> 1554775786 -0700
committer Sijie Guo <guosijie@gmail.com> 1554775786 +0800

[pulsar-storm] Fix NPE while emitting next tuple (#3991)

### Motivation

[PulsarSpout] removes messages from [pendingMessageRetries](https://github.com/apache/pulsar/blob/master/pulsar-storm/src/main/java/org/apache/pulsar/storm/PulsarSpout.java#L126) but it doesn't remove from the `failedMessages` queue because of that PulsarSpout throws NPE while [emitting next tuple](https://github.com/apache/pulsar/blob/master/pulsar-storm/src/main/java/org/apache/pulsar/storm/PulsarSpout.java#L181)

````
stack-trace with old pulsar-storm lib: 1.20
2019-04-05 18:49:58.240 b.s.util CmsSpout_[1 1] [INFO] Async loop Stacktrace is: {} java.lang.NullPointerException
    at org.apache.pulsar.storm.PulsarSpout.emitNextAvailableTuple(PulsarSpout.java:176)
    at org.apache.pulsar.storm.PulsarSpout.nextTuple(PulsarSpout.java:160)
    at backtype.storm.daemon.executor$fn__7365$fn__7380$fn__7411.invoke(executor.clj:577)
    at backtype.storm.util$async_loop$fn__551.invoke(util.clj:491)
    at clojure.lang.AFn.run(AFn.java:22)
    at java.lang.Thread.run(Thread.java:748)
```