Why don't you see how it can return null? I'm looking at an older checkout, but I see JettySolrRunner checking for null core containers all over, and I see it passing back null explicitly in at least one case.
When I peek at where that core container might be coming from, I see a provider and a field that looks like it's home (which I note doesn't look protected by any memory barrier? e.g., volatile, lock, sync). And I see that it could start as null. Get set to null on close as well? So I wonder about that lack of a memory barrier, but there are probably plenty of cases where some random jobs/threads are still running past that close as well, is another thought I have. And I bet one of them comes in and looks for that core container late, and he's already clocked out. Older checkout, so I don't know what you are looking at, but if it hasn't changed drastically recently, it seems easy to return a null. If you want to duplicate a situation that might hit - try running the test with 10-20 instances simultaneously looped. Or loop one, and hammer your system with some unrelated load for a while. On Thu, Jun 15, 2023 at 4:49 PM Alex Deparvu <stilla...@apache.org> wrote: > Hi, > > I wanted to take a look at the flaky DeleteReplicaTest test. > > Some background first: > - Past 7 days trend: > Class: org.apache.solr.cloud.DeleteReplicaTest > Method: raceConditionOnDeleteAndRegisterReplica > Failures: 15.56% (63 / 405) > > - Test failure is caused by a NullPointerException: > ERROR (coreZkRegister-772-thread-1-processing-127.0.0.1:40471_solr) > [n:127.0.0.1:40471_solr c:raceDeleteReplicaCollection s:shard1 > r:core_node4 > x:raceDeleteReplicaCollection_shard1_replica_n2] o.a.s.c.DeleteReplicaTest > Failed to delete replica > => java.lang.NullPointerException: Cannot invoke > "org.apache.solr.core.CoreContainer.getZkController()" because the return > value of "org.apache.solr.embedded.JettySolrRunner.getCoreContainer()" is > null > > I am having some trouble reproducing on my local and I don't see how the > getCoreContainer() method might return null. Could this be a timing issue > somehow? > If anyone has an idea on how to approach this, I would be happy to hear it. > > best, > alex > -- - MRM
