Update to 1309.ve21874387edf logs NullPointerException when old build is discarded

[PayBas]

Jenkins and plugins versions report

Environment

Jenkins: 2.462.2
OS: Linux - 6.10.10-200.fc40.x86_64
Java: 11.0.24 - Red Hat, Inc. (OpenJDK 64-Bit Server VM)
---

What Operating System are you using (both controller, and any agents involved in the problem)?

Fedora 40, both for controller and agents

Reproduction steps

1. Have a pipeline job that uses a lockable resource.
2. Set a "Discard old builds" option with "Log Rotation" strategy and "Max # of builds to keep" = 3.
3. Run the pipeline job 4 times.
4. Observe the Jenkins controller logs.

Expected Results

No NPE

Actual Results

Sep 20, 2024 12:50:28 AM INFO org.jenkins.plugins.lockableresources.queue.LockRunListener onDeleted
my-pipeline-job resource1
Sep 20, 2024 12:50:28 AM WARNING jenkins.util.Listeners lambda$notify$0
null
java.lang.NullPointerException
	at PluginClassLoader for lockable-resources//org.jenkins.plugins.lockableresources.LockableResourcesManager.unlockBuild(LockableResourcesManager.java:655)
	at PluginClassLoader for lockable-resources//org.jenkins.plugins.lockableresources.queue.LockRunListener.onDeleted(LockRunListener.java:110)
	at hudson.model.listeners.RunListener.lambda$fireDeleted$4(RunListener.java:271)
	at jenkins.util.Listeners.lambda$notify$0(Listeners.java:59)
	at jenkins.util.Listeners.notify(Listeners.java:67)
	at hudson.model.listeners.RunListener.fireDeleted(RunListener.java:269)
	at hudson.model.Run.delete(Run.java:1646)
	at hudson.tasks.LogRotator.perform(LogRotator.java:167)
	at hudson.model.Job.logRotate(Job.java:486)
	at jenkins.model.JobGlobalBuildDiscarderStrategy.apply(JobGlobalBuildDiscarderStrategy.java:54)
	at jenkins.model.BackgroundGlobalBuildDiscarder.lambda$processJob$0(BackgroundGlobalBuildDiscarder.java:67)
	at java.base/java.lang.Iterable.forEach(Iterable.java:75)
	at jenkins.model.BackgroundGlobalBuildDiscarder.processJob(BackgroundGlobalBuildDiscarder.java:61)
	at jenkins.model.BackgroundGlobalBuildDiscarder.execute(BackgroundGlobalBuildDiscarder.java:55)
	at hudson.model.AsyncPeriodicWork.lambda$doRun$0(AsyncPeriodicWork.java:102)
	at java.base/java.lang.Thread.run(Thread.java:829)

Anything else?

No response

Are you interested in contributing a fix?

No response

[jimklimov]

FWIW, this seems to be one of changes from PR #673, with new methods and lines at

lockable-resources-plugin/src/main/java/org/jenkins/plugins/lockableresources/LockableResourcesManager.java

Lines 646 to 659 in e218743

	public void unlockBuild(@Nullable Run<?, ?> build) {
	if (build == null) {
	return;
	}
	List<String> resourcesInUse =
	LockedResourcesBuildAction.findAndInitAction(build).getCurrentUsedResourceNames();
	if (resourcesInUse.size() == 0) {
	return;
	}
	unlockNames(resourcesInUse, build);
	}

An NPE at line 655 probably means resourcesInUse.size() failed because resourcesInUse == null.

One chance for that could be findAndInitAction() returning null (e.g. because build is null, which could make sense during deletion but we check just above that it is not - and a null at this point would throw NPE to call the next method in chain):

• lockable-resources-plugin/src/main/java/org/jenkins/plugins/lockableresources/actions/LockedResourcesBuildAction.java

  Lines 63 to 79 in e218743

  	public static LockedResourcesBuildAction findAndInitAction(final Run<?, ?> build) {
  	if (build == null) {
  	return null;
  	}
  	LockedResourcesBuildAction action;
  	synchronized (build) {
  	List<LockedResourcesBuildAction> actions = build.getActions(LockedResourcesBuildAction.class);
  	if (actions.size() <= 0) {
  	action = new LockedResourcesBuildAction();
  	build.addAction(action);
  	} else {
  	action = actions.get(0);
  	}
  	}
  	return action;
  	}

...or getCurrentUsedResourceNames() returning null because that what resourcesInUse would be?.. should not happen either, it is pre-initialized and never deleted AFAIK.

• lockable-resources-plugin/src/main/java/org/jenkins/plugins/lockableresources/actions/LockedResourcesBuildAction.java

  Lines 47 to 49 in e218743

  	public List<String> getCurrentUsedResourceNames() {
  	return resourcesInUse;
  	}

• lockable-resources-plugin/src/main/java/org/jenkins/plugins/lockableresources/actions/LockedResourcesBuildAction.java

  Line 25 in e218743

  private List<String> resourcesInUse = new ArrayList<>();

[Udo10744]

We have the same issue on Windows Server/Slaves, with a lightly different/detailed error message: Cannot invoke "java.util.List.size()" because "resourcesInUse" is null

2024-10-14 04:02:33.222+0000 [id=3374] INFO o.j.p.l.queue.LockRunListener#onDeleted: VCCP » A9 » Full #274 2024-10-14 04:02:33.222+0000 [id=3374] WARNING jenkins.util.Listeners#lambda$notify$0 java.lang.NullPointerException: Cannot invoke "java.util.List.size()" because "resourcesInUse" is null at PluginClassLoader for lockable-resources//org.jenkins.plugins.lockableresources.LockableResourcesManager.unlockBuild(LockableResourcesManager.java:655) at PluginClassLoader for lockable-resources//org.jenkins.plugins.lockableresources.queue.LockRunListener.onDeleted(LockRunListener.java:110) at hudson.model.listeners.RunListener.lambda$fireDeleted$4(RunListener.java:271) at jenkins.util.Listeners.lambda$notify$0(Listeners.java:59) at jenkins.util.Listeners.notify(Listeners.java:67) at hudson.model.listeners.RunListener.fireDeleted(RunListener.java:269) at hudson.model.Run.delete(Run.java:1646) at hudson.tasks.LogRotator.perform(LogRotator.java:182) at jenkins.model.SimpleGlobalBuildDiscarderStrategy.apply(SimpleGlobalBuildDiscarderStrategy.java:61) at jenkins.model.BackgroundGlobalBuildDiscarder.lambda$processJob$0(BackgroundGlobalBuildDiscarder.java:64) at java.base/java.lang.Iterable.forEach(Iterable.java:75) at jenkins.model.BackgroundGlobalBuildDiscarder.processJob(BackgroundGlobalBuildDiscarder.java:60) at jenkins.model.BackgroundGlobalBuildDiscarder.execute(BackgroundGlobalBuildDiscarder.java:55) at hudson.model.AsyncPeriodicWork.lambda$doRun$0(AsyncPeriodicWork.java:102) at java.base/java.lang.Thread.run(Thread.java:1583)