ConcurrentModificationException in CodeBuildAction

I am using:

Jenkins: 2.89.3
AWS Codebuild plugin: com.amazonaws:aws-codebuild:0.17 (maven ID)
Pipeline plugin: org.jenkins-ci.plugins.workflow:workflow-aggregator:2.5 (maven ID)

And I have a multibranch pipeline with Jenkinsfile which looks something like this:

```
pipeline {
agent { label 'master' }

stages {
stage('Checkout') {
steps {
checkout scm
}
}
stage('Test Run') {
failFast true
parallel {
stage('Test Run 1') {
steps {
timestamps {
withCredentials([[$class: 'AmazonWebServicesCredentialsBinding', credentialsId: 'aws']]) {
awsCodeBuild credentialsId: 'CodeBuild', credentialsType: 'jenkins', projectName: 'Proj1', region: 'us-east-1', sourceControlType: 'project', sourceVersion: "${env.GIT_COMMIT}"
}
}
}
}
stage('Test Run 2') {
steps {
withCredentials([[$class: 'AmazonWebServicesCredentialsBinding', credentialsId: 'aws']]) {
awsCodeBuild credentialsId: 'CodeBuild', credentialsType: 'jenkins', projectName: 'Proj2', region: 'us-east-1', sourceControlType: 'project', sourceVersion: "${env.GIT_COMMIT}"
}
}
}
stage('Test Run 3') {
steps {
withCredentials([[$class: 'AmazonWebServicesCredentialsBinding', credentialsId: 'aws']]) {
awsCodeBuild credentialsId: 'CodeBuild', credentialsType: 'jenkins', projectName: 'Proj3', region: 'us-east-1', sourceControlType: 'project', sourceVersion: "${env.GIT_COMMIT}", envVariables: "[{VAR, value1}]"
}
}
}
stage('Test Run 4') {
steps {
withCredentials([[$class: 'AmazonWebServicesCredentialsBinding', credentialsId: 'aws']]) {
awsCodeBuild credentialsId: 'CodeBuild', credentialsType: 'jenkins', projectName: 'Proj3', region: 'us-east-1', sourceControlType: 'project', sourceVersion: "${env.GIT_COMMIT}", envVariables: "[{VAR, value2}]"
}
}
}
stage('Test Run 5') {
steps {
withCredentials([[$class: 'AmazonWebServicesCredentialsBinding', credentialsId: 'aws']]) {
awsCodeBuild credentialsId: 'CodeBuild', credentialsType: 'jenkins', projectName: 'Proj3', region: 'us-east-1', sourceControlType: 'project', sourceVersion: "${env.GIT_COMMIT}", envVariables: "[{VAR, value3}]"
}
}
}
stage('Test Run 6') {
steps {
withCredentials([[$class: 'AmazonWebServicesCredentialsBinding', credentialsId: 'aws']]) {
awsCodeBuild credentialsId: 'CodeBuild', credentialsType: 'jenkins', projectName: 'Proj3', region: 'us-east-1', sourceControlType: 'project', sourceVersion: "${env.GIT_COMMIT}", envVariables: "[{VAR, value4}]"
}
}
}
}
}
}
}
```

in stages `Test Run 3` to `Test Run 6` I am using same Codebuild project but with different environment variable values which execute different scripts in the build
When I am running the job with above pipeline I am getting following exception:

```
java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:907)
at java.util.ArrayList$Itr.next(ArrayList.java:857)
at com.thoughtworks.xstream.converters.collections.CollectionConverter.marshal(CollectionConverter.java:73)
at com.thoughtworks.xstream.core.AbstractReferenceMarshaller.convert(AbstractReferenceMarshaller.java:69)
at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:58)
at com.thoughtworks.xstream.core.AbstractReferenceMarshaller$1.convertAnother(AbstractReferenceMarshaller.java:84)
at hudson.util.RobustReflectionConverter.marshallField(RobustReflectionConverter.java:265)
at hudson.util.RobustReflectionConverter$2.writeField(RobustReflectionConverter.java:252)
Caused: java.lang.RuntimeException: Failed to serialize CodeBuildAction#logs for class CodeBuildAction
at hudson.util.RobustReflectionConverter$2.writeField(RobustReflectionConverter.java:256)
at hudson.util.RobustReflectionConverter$2.visit(RobustReflectionConverter.java:224)
at com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider.visitSerializableFields(PureJavaReflectionProvider.java:138)
at hudson.util.RobustReflectionConverter.doMarshal(RobustReflectionConverter.java:209)
at hudson.util.RobustReflectionConverter.marshal(RobustReflectionConverter.java:150)
at com.thoughtworks.xstream.core.AbstractReferenceMarshaller.convert(AbstractReferenceMarshaller.java:69)
at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:58)
at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:43)
at com.thoughtworks.xstream.core.AbstractReferenceMarshaller$1.convertAnother(AbstractReferenceMarshaller.java:88)
at com.thoughtworks.xstream.converters.collections.AbstractCollectionConverter.writeItem(AbstractCollectionConverter.java:64)
at com.thoughtworks.xstream.converters.collections.CollectionConverter.marshal(CollectionConverter.java:74)
at com.thoughtworks.xstream.core.AbstractReferenceMarshaller.convert(AbstractReferenceMarshaller.java:69)
at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:58)
at com.thoughtworks.xstream.core.AbstractReferenceMarshaller$1.convertAnother(AbstractReferenceMarshaller.java:84)
at hudson.util.RobustReflectionConverter.marshallField(RobustReflectionConverter.java:265)
at hudson.util.RobustReflectionConverter$2.writeField(RobustReflectionConverter.java:252)
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:256)
at hudson.util.RobustReflectionConverter$2.visit(RobustReflectionConverter.java:224)
at com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider.visitSerializableFields(PureJavaReflectionProvider.java:138)
at hudson.util.RobustReflectionConverter.doMarshal(RobustReflectionConverter.java:209)
at hudson.util.RobustReflectionConverter.marshal(RobustReflectionConverter.java:150)
at com.thoughtworks.xstream.core.AbstractReferenceMarshaller.convert(AbstractReferenceMarshaller.java:69)
at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:58)
at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:43)
at com.thoughtworks.xstream.core.TreeMarshaller.start(TreeMarshaller.java:82)
at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.marshal(AbstractTreeMarshallingStrategy.java:37)
at com.thoughtworks.xstream.XStream.marshal(XStream.java:1026)
at com.thoughtworks.xstream.XStream.marshal(XStream.java:1015)
at com.thoughtworks.xstream.XStream.toXML(XStream.java:988)
at hudson.XmlFile.write(XmlFile.java:181)
at org.jenkinsci.plugins.workflow.support.PipelineIOUtils.writeByXStream(PipelineIOUtils.java:30)
at org.jenkinsci.plugins.workflow.job.WorkflowRun.save(WorkflowRun.java:1070)
at hudson.BulkChange.commit(BulkChange.java:98)
at org.jenkinsci.plugins.workflow.cps.CpsFlowExecution.notifyListeners(CpsFlowExecution.java:1377)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$3.run(CpsThreadGroup.java:412)
at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$1.run(CpsVmExecutorService.java:35)
at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:112)
at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Finished: FAILURE
```

I am not familiar with Jenkins plugins, can anyone suggest any pointers, where can I look for more information, etc.

Start at CodeBuildAction#logs and follow the serialization path shown through XStream, WorkflowRun.save, and PipelineIOUtils.writeByXStream. Reproduce the failure with the parallel Jenkinsfile and confirm that concurrent CodeBuild executions can be persisted without the ConcurrentModificationException while retaining their logs.

Written by the indexing model from the issue text.