ConcurrentModificationException: Failed to serialize org.jenkinsci.plugins.githubautostatus.BuildStatusAction#buildStatuses

[jimklimov]

Jenkins and plugins versions report

Part of https://issues.jenkins.io/browse/JENKINS-76294

Expected solution: similar to jenkinsci/lockable-resources-plugin#825

Visible problem: jobs occasionally crash when server (or other actions, like work with badges or lockable resources) decide to cause a WorkflowRun serialization, and the plugin changes underlying data at the wrong moment. As a clue, server and/or build logs then contain something like:

2025-10-22 05:06:05.328+0000 [id=75483] WARNING o.j.p.workflow.steps.scm.SCMStep#checkout
java.util.ConcurrentModificationException
        at java.base/java.util.HashMap$HashIterator.nextNode(HashMap.java:1605)
        at java.base/java.util.HashMap$EntryIterator.next(HashMap.java:1638)
        at java.base/java.util.HashMap$EntryIterator.next(HashMap.java:1636)
        at com.thoughtworks.xstream.converters.collections.MapConverter.marshal(MapConverter.java:76)
        at com.thoughtworks.xstream.core.AbstractReferenceMarshaller.convert(AbstractReferenceMarshaller.java:68)
        at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:59)
        at com.thoughtworks.xstream.core.AbstractReferenceMarshaller$1.convertAnother(AbstractReferenceMarshaller.java:83)
        at hudson.util.RobustReflectionConverter.marshallField(RobustReflectionConverter.java:285)
        at hudson.util.RobustReflectionConverter$2.writeField(RobustReflectionConverter.java:272)
Caused: java.lang.RuntimeException: Failed to serialize org.jenkinsci.plugins.githubautostatus.BuildStatusAction#buildStatuses for class org.jenkinsci.plugins.githubautostatus.BuildStatusAction
        at hudson.util.RobustReflectionConverter$2.writeField(RobustReflectionConverter.java:276)
        at hudson.util.RobustReflectionConverter$2.visit(RobustReflectionConverter.java:243)
        at com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider.visitSerializableFields(PureJavaReflectionProvider.java:174)
        at hudson.util.RobustReflectionConverter.doMarshal(RobustReflectionConverter.java:228)
        at hudson.util.RobustReflectionConverter.marshal(RobustReflectionConverter.java:165)
        at com.thoughtworks.xstream.core.AbstractReferenceMarshaller.convert(AbstractReferenceMarshaller.java:68)
        at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:59)
        at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:44)
        at com.thoughtworks.xstream.core.AbstractReferenceMarshaller$1.convertAnother(AbstractReferenceMarshaller.java:87)
        at com.thoughtworks.xstream.converters.collections.AbstractCollectionConverter.writeBareItem(AbstractCollectionConverter.java:94)
        at com.thoughtworks.xstream.converters.collections.AbstractCollectionConverter.writeItem(AbstractCollectionConverter.java:66)
        at com.thoughtworks.xstream.converters.collections.AbstractCollectionConverter.writeCompleteItem(AbstractCollectionConverter.java:81)
        at com.thoughtworks.xstream.converters.collections.CollectionConverter.marshal(CollectionConverter.java:75)
        at com.thoughtworks.xstream.core.AbstractReferenceMarshaller.convert(AbstractReferenceMarshaller.java:68)
        at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:59)
        at com.thoughtworks.xstream.core.AbstractReferenceMarshaller$1.convertAnother(AbstractReferenceMarshaller.java:83)
        at hudson.util.RobustReflectionConverter.marshallField(RobustReflectionConverter.java:285)
        at hudson.util.RobustReflectionConverter$2.writeField(RobustReflectionConverter.java:272)
Caused: java.lang.RuntimeException: Failed to serialize hudson.model.Actionable#actions for class org.jenkinsci.plugins.workflow.job.WorkflowRun
        at hudson.util.RobustReflectionConverter$2.writeField(RobustReflectionConverter.java:276)
        at hudson.util.RobustReflectionConverter$2.visit(RobustReflectionConverter.java:243)
        at com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider.visitSerializableFields(PureJavaReflectionProvider.java:174)
        at hudson.util.RobustReflectionConverter.doMarshal(RobustReflectionConverter.java:228)
        at hudson.util.RobustReflectionConverter.marshal(RobustReflectionConverter.java:165)
        at com.thoughtworks.xstream.core.AbstractReferenceMarshaller.convert(AbstractReferenceMarshaller.java:68)
        at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:59)
        at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:44)
        at com.thoughtworks.xstream.core.TreeMarshaller.start(TreeMarshaller.java:83)
        at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.marshal(AbstractTreeMarshallingStrategy.java:37)
        at com.thoughtworks.xstream.XStream.marshal(XStream.java:1307)
        at com.thoughtworks.xstream.XStream.marshal(XStream.java:1296)
        at com.thoughtworks.xstream.XStream.toXML(XStream.java:1269)
        at hudson.util.XStream2.toXMLUTF8(XStream2.java:386)
        at PluginClassLoader for workflow-support//org.jenkinsci.plugins.workflow.support.PipelineIOUtils.writeByXStream(PipelineIOUtils.java:34)
        at PluginClassLoader for workflow-job//org.jenkinsci.plugins.workflow.job.WorkflowRun.save(WorkflowRun.java:1264)
        at hudson.util.PersistedList.onModified(PersistedList.java:190)
        at hudson.util.PersistedList._onModified(PersistedList.java:221)
        at hudson.util.PersistedList.add(PersistedList.java:82)
        at PluginClassLoader for workflow-job//org.jenkinsci.plugins.workflow.job.WorkflowRun.onCheckout(WorkflowRun.java:920)
        at PluginClassLoader for workflow-job//org.jenkinsci.plugins.workflow.job.WorkflowRun$SCMListenerImpl.onCheckout(WorkflowRun.java:1218)
        at PluginClassLoader for workflow-scm-step//org.jenkinsci.plugins.workflow.steps.scm.SCMStep.checkout(SCMStep.java:182)
        at PluginClassLoader for workflow-scm-step//org.jenkinsci.plugins.workflow.steps.scm.SCMStep$StepExecutionImpl.run(SCMStep.java:101)
        at PluginClassLoader for workflow-scm-step//org.jenkinsci.plugins.workflow.steps.scm.SCMStep$StepExecutionImpl.run(SCMStep.java:88)
        at PluginClassLoader for workflow-step-api//org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution.lambda$start$0(SynchronousNonBlockingStepExecution.java:49)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
        at java.base/java.lang.Thread.run(Thread.java:1583)

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

Jenkins LTS 2.528.1 and several before it
OpenIndiana, Linux

Reproduction steps

Probably involves jobs with a number of parallel stages, where each could do something that triggers a workflow save. Will try to conjure up a repro test case as part of work on the issue.

Expected Results

CME does not happen, noise is not logged, jobs do not crash.

Actual Results

Occasionally complex and long-running jobs are terminated due to no fault of the tested code (rather as part of exception handling with failed serialization).

Anything else?

No response

Are you interested in contributing a fix?

yes

[kunalmali83]

I have to work on this issue thoroughly. Please assign it to me.

[jimklimov]

@kunalmali83 : sorry, I missed that comment of yours earlier. I am not a maintainer here, so can't "assign" this to you. As with FOSS, you can just pick it up and propose a fix anyway. Note that I've posted some PRs to reproduce the issue the best we can in automated tests (so it is easier to be sure a fix works).

In fact, a custom build from PR #181 seems to fix the issue for me, but if you have any ways to work in this more "thoroughly" - be my guest. The Jenkins CI farm did dislike something in that branch, though I did not have time to look into that since.