Failing to iterate list with workflow

[David Resnick]

I'm trying create jobs to run in parallel in a workflow with this script:

def branches = [:]

def jobs = [ 'job-1' ]

for (job in jobs) {

    branches[job] = { build job: job }

}

parallel branches

This fails with the below (though it doesn't fail when 'parallel branches' is commented out).

How can this be done?

Thanks,

David

Running: Execute sub-workflows in parallel : Start
[job-1] Running: Parallel branch: job-1
[job-1] Running: Build a Job
[job-1] Starting building project: job-1
Running: Execute sub-workflows in parallel : Body : End
Running: End of Workflow
java.io.NotSerializableException: java.util.ArrayList$Itr
	at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:860)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:967)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
	at org.jboss.marshalling.river.BlockMarshaller.doWriteObject(BlockMarshaller.java:65)
	at org.jboss.marshalling.river.BlockMarshaller.writeObject(BlockMarshaller.java:56)
	at org.jboss.marshalling.MarshallerObjectOutputStream.writeObjectOverride(MarshallerObjectOutputStream.java:50)
	at org.jboss.marshalling.river.RiverObjectOutputStream.writeObjectOverride(RiverObjectOutputStream.java:179)
	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:344)
	at java.util.HashMap.internalWriteEntries(HashMap.java:1777)
	at java.util.HashMap.writeObject(HashMap.java:1354)
	at sun.reflect.GeneratedMethodAccessor144.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:497)
	at org.jboss.marshalling.reflect.SerializableClass.callWriteObject(SerializableClass.java:271)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:976)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
	at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
	at org.jboss.marshalling.AbstractObjectOutput.writeObject(AbstractObjectOutput.java:58)
	at org.jboss.marshalling.AbstractMarshaller.writeObject(AbstractMarshaller.java:111)
	at org.jenkinsci.plugins.workflow.support.pickles.serialization.RiverWriter.writeObject(RiverWriter.java:133)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.saveProgram(CpsThreadGroup.java:344)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.saveProgram(CpsThreadGroup.java:328)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:303)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$000(CpsThreadGroup.java:71)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:180)
	at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:178)
	at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:47)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	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:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Caused by: an exception which occurred:
	in field itr
	in field target
	in field continue_
	in field parent
	in field capture
	in field def
	in field closures
	in object org.jenkinsci.plugins.workflow.cps.CpsThreadGroup@2dbe3b3c
Finished: FAILURE

[Arek Skalski]

Try to use classic:
 for(int i = 0 ; i < jobs.length(); ++i) {...}

[David Resnick]

Thanks!

This is indeed another case of https://issues.jenkins-ci.org/browse/JENKINS-27421

Here is a working snippet:

def branches = [:]

def jobs = [ 'job-1' ]

def jobName

for (int i = 0; i < jobs.size(); i++) {

    jobName = jobs[i]

    // jobName must be used inside the build job closure

    branches[jobName] = { build job: jobName }

}

parallel branches

- David