Fixed assertion unsafe call of ClusterService.state()

[nibix]

Description

I have been recently reviewing test logs of the security plugin and found large amounts of test failures caused by this assertion error:

2025-10-26T20:04:25.1579948Z     java.lang.AssertionError: initial cluster state not set yet
2025-10-26T20:04:25.1580807Z         at org.opensearch.cluster.service.ClusterApplierService.state(ClusterApplierService.java:239)
2025-10-26T20:04:25.1581827Z         at org.opensearch.cluster.service.ClusterService.state(ClusterService.java:187)
2025-10-26T20:04:25.1583236Z         at org.opensearch.node.ResourceUsageCollectorService.collectLocalNodeResourceUsageStats(ResourceUsageCollectorService.java:129)
2025-10-26T20:04:25.1584928Z         at org.opensearch.node.ResourceUsageCollectorService.lambda$doStart$3(ResourceUsageCollectorService.java:147)
2025-10-26T20:04:25.1586094Z         at org.opensearch.threadpool.Scheduler$ReschedulingRunnable.doRun(Scheduler.java:246)
2025-10-26T20:04:25.1587410Z         at org.opensearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:975)
2025-10-26T20:04:25.1588919Z         at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:52)
2025-10-26T20:04:25.1589916Z         at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1095)
2025-10-26T20:04:25.1590927Z         at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:619)
2025-10-26T20:04:25.1591709Z         at java.base/java.lang.Thread.run(Thread.java:1447)

(source)

This is caused by this code:

OpenSearch/server/src/main/java/org/opensearch/node/ResourceUsageCollectorService.java

Lines 128 to 138 in 753c135

	private void collectLocalNodeResourceUsageStats() {
	if (nodeResourceUsageTracker.isReady() && clusterService.state() != null) {
	collectNodeResourceUsageStats(
	clusterService.state().nodes().getLocalNodeId(),
	System.currentTimeMillis(),
	nodeResourceUsageTracker.getMemoryUtilizationPercent(),
	nodeResourceUsageTracker.getCpuUtilizationPercent(),
	nodeResourceUsageTracker.getIoUsageStats()
	);
	}
	}

If you examine ClusterApplierService.state(), you will see that it will throw an assertion error if clusterState is still null, something that will happen during early cluster initialization phases. Thus, the test clusterService.state() is bogus, as it won't guard the code in environments with assertions enabled:

OpenSearch/server/src/main/java/org/opensearch/cluster/service/ClusterApplierService.java

Lines 236 to 241 in 753c135

	public ClusterState state() {
	assert assertNotCalledFromClusterStateApplier("the applied cluster state is not yet available");
	ClusterState clusterState = this.state.get();
	assert clusterState != null : "initial cluster state not set yet";
	return clusterState;
	}

One should use clusterService.isStateInitialised() instead to perform the check assertion-safe.

Check List

• Functionality includes testing: manually tested

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[github-actions]

❌ Gradle check result for 0fc2db2: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❌ Gradle check result for 004694d: null

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❌ Gradle check result for 004694d: null

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

✅ Gradle check result for 004694d: SUCCESS

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 73.13%. Comparing base (753c135) to head (004694d).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...opensearch/node/ResourceUsageCollectorService.java	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #19775      +/-   ##
============================================
+ Coverage     73.10%   73.13%   +0.02%     
+ Complexity    70959    70958       -1     
============================================
  Files          5737     5737              
  Lines        324766   324766              
  Branches      46981    46981              
============================================
+ Hits         237425   237507      +82     
+ Misses        68226    68110     -116     
- Partials      19115    19149      +34     

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