NotSerializableException in jenkinsfile

Question

I'm working on a jenkinsfile and I'm getting and exception in the third stage:

an exception which occurred:
in field com.cloudbees.groovy.cps.impl.BlockScopeEnv.locals
in object com.cloudbees.groovy.cps.impl.BlockScopeEnv@7bbae4fb
in field com.cloudbees.groovy.cps.impl.ProxyEnv.parent
in object com.cloudbees.groovy.cps.impl.CaseEnv@6896a2e3
in field com.cloudbees.groovy.cps.impl.ProxyEnv.parent
in object com.cloudbees.groovy.cps.impl.BlockScopeEnv@605ccbbc
in field com.cloudbees.groovy.cps.impl.CallEnv.caller
in object com.cloudbees.groovy.cps.impl.FunctionCallEnv@7b8ef914
in field com.cloudbees.groovy.cps.Continuable.e
in object org.jenkinsci.plugins.workflow.cps.SandboxContinuable@11e73f3c
in field org.jenkinsci.plugins.workflow.cps.CpsThread.program
in object org.jenkinsci.plugins.workflow.cps.CpsThread@b2df9bb
in field org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.threads
in object org.jenkinsci.plugins.workflow.cps.CpsThreadGroup@2b30596a
in object org.jenkinsci.plugins.workflow.cps.CpsThreadGroup@2b30596a
Caused: java.io.NotSerializableException: java.util.regex.Matcher
    at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:860)
    at org.jboss.marshalling.river.BlockMarshaller.doWriteObject(BlockMarshaller.java:65)
    at org.jboss.marshalling.river.BlockMarshaller.writeObject(BlockMarshaller.java:56)

I've been reading about it and I know I can't create non-serializable variables. So, I think it has to be with this part of my code:

def artifact_name = sh (
        script: "ls -b *.jar | head -1",
        returnStdout: true
).trim()
def has_snapshot = artifact_name =~ /-TEST\.jar/
if (has_snapshot) {
    //Do something
}

My question is, how do I define that two variables in order to avoid that exception?

Solution

Your problem is this line:

def has_snapshot = artifact_name =~ /-TEST\.jar/

The =~ is the Groovy find operator. It returns a java.util.regex.Matcher instance, which is not Serializable. If Jenkins decides to pause your script after you have stored the result in a local variable that is serialized by Jenkins that is when you get the exception. This can be easily tested by immediately adding a sleep(1) step after your invocation and watch as that same exception is thrown.

To resolve this, you should :

• Not store the java.util.regex.Matcher result in CPS transformed code
• Move the usage into a @NonCPS annotated method or use the match operator (==~) which returns a boolean (if it fits your use case)

Comments

[Jaime Alcántara Arnela]

Sorry to take so long to comment but the expresion is now always returning false with the ==~ (when the artifact name is "artifact.x.y.z-TEST.jar" and when it is "artifact.x.y.z.jar"), so the has_snapshot is always false. Am I skiping something?

[mkobit]

@JaimeAlcántaraArnela make sure you look at the full documentation of the match operator. It "requires a strict match of the input string". So, if you change your pattern from /-TEST\.jar/ to something like /.*-TEST\.jar/ you may/may not get the expected result. I would recommend trying it out in a Groovy Shell to get a feel for you it works.

[Lee Meador]

I had a similar error when I was iteration over a map with "for (def entry in myMap)" and calling another Jenkins build job. The other job would run but this job would fail with this error immediately, before the other job completed. I thought the wait option was being ignored.