[SOLR-9030] The 'downnode' command can trip asserts in ZkStateWriter

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 5.5.2, 5.6, 6.0.1, 6.1, 7.0
• Component/s: SolrCloud
• Assignee: Shalin Shekhar Mangar
• Reporter: Shalin Shekhar Mangar
• Created: 22/Apr/16 13:43
• Updated: 02/Oct/19 17:24
• Resolved: 17/Jun/16 20:57

Description

While working on SOLR-9014 I came across a strange test failure.

   [junit4] ERROR   16.9s | AsyncCallRequestStatusResponseTest.testAsyncCallStatusResponse <<<
   [junit4]    > Throwable #1: com.carrotsearch.randomizedtesting.UncaughtExceptionError: Captured an uncaught exception in thread: Thread[id=46, name=OverseerStateUpdate-95769832112259076-127.0.0.1:51135_z_oeg%2Ft-n_0000000000, state=RUNNABLE, group=Overseer state updater.]
   [junit4]    > 	at __randomizedtesting.SeedInfo.seed([91F68DA7E10807C3:CBF7E84BCF328A1A]:0)
   [junit4]    > Caused by: java.lang.AssertionError
   [junit4]    > 	at __randomizedtesting.SeedInfo.seed([91F68DA7E10807C3]:0)
   [junit4]    > 	at org.apache.solr.cloud.overseer.ZkStateWriter.writePendingUpdates(ZkStateWriter.java:231)
   [junit4]    > 	at org.apache.solr.cloud.Overseer$ClusterStateUpdater.run(Overseer.java:240)
   [junit4]    > 	at java.lang.Thread.run(Thread.java:745)

The underlying problem can manifest by tripping the above assert or a BadVersionException as well. I found that this was introduced in SOLR-7281 where a new 'downnode' command was added.