NPE while restarting ES in docker

[shushu992]

Elasticsearch Version

Version: 8.15.2, Build: docker/98adf7bf6bb69b66ab95b761c9e5aadb0bb059a3/2024-09-19T10:06:03.564235954Z, JVM: 22.0.1

Installed Plugins

analysis-icu

Java Version

bundled

OS Version

Linux vm-debian 6.1.0-26-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.112-1 (2024-09-30) x86_64 GNU/Linux

Problem Description

I am running an ES in docker with plugins installed by elasticsearch-plugins.yml.
The first run was working well.
When I restart the container, it'll throw a NullPointerException and stop.

Steps to Reproduce

1. Prepare elasticsearch-plugins.yml

plugins:
  - id: analysis-icu

2. Create a container

docker create docker.elastic.co/elasticsearch/elasticsearch:8.15.2

3. Copy configuration

docker cp elasticsearch-plugins.yml xxx:/usr/share/elasticsearch/config/elasticsearch-plugins.yml

4. Run initially （It's working properly)

docker start xxx

5. Restart (It's throwing NPE)

docker restart xxx

Logs (if relevant)

java.lang.NullPointerException
	at java.base/java.util.Objects.requireNonNull(Objects.java:220)
	at java.base/java.util.stream.Collectors.lambda$uniqKeysMapAccumulator$1(Collectors.java:180)
	at java.base/java.util.stream.ReduceOps$3ReducingSink.accept(ReduceOps.java:169)
	at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1709)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:556)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:546)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:265)
	at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:702)
	at org.elasticsearch.plugins.cli.SyncPluginsAction.lambda$getPluginsToUpgrade$2(SyncPluginsAction.java:210)
	at java.base/java.util.Optional.map(Optional.java:260)
	at org.elasticsearch.plugins.cli.SyncPluginsAction.getPluginsToUpgrade(SyncPluginsAction.java:209)
	at org.elasticsearch.plugins.cli.SyncPluginsAction.getPluginChanges(SyncPluginsAction.java:133)
	at org.elasticsearch.plugins.cli.SyncPluginsAction.execute(SyncPluginsAction.java:101)
	at org.elasticsearch.plugins.cli.SyncPluginsCliProvider$1.execute(SyncPluginsCliProvider.java:49)
	at org.elasticsearch.server.cli.ServerCli.syncPlugins(ServerCli.java:206)
	at org.elasticsearch.server.cli.ServerCli.execute(ServerCli.java:98)
	at org.elasticsearch.common.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:54)
	at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:94)
	at org.elasticsearch.cli.Command.main(Command.java:51)
	at org.elasticsearch.launcher.CliToolLauncher.main(CliToolLauncher.java:64)

[elasticsearchmachine]

Pinging @elastic/es-core-infra (Team:Core/Infra)

[ldematte]

I have investigated this a little bit. It is reproducible.
I think it can be a simple fix, but I'll have an expert opinion to see if it's OK.