I have a simple worflow job which runs this script:

def r = new aldebaran.agbuild.MyRunner()
r.runme_ko()

using this groovy library:

$ cat src/aldebaran/agbuild/MyRunner.groovy 
package aldebaran.agbuild;

//class MyParameters implements Serializable {
class MyParameters {
  Boolean sync = true;
}
def runme_ko() {
  stage name: 'run_stage', concurrency: 10
  def myparams = new MyParameters();
  node("qisrc") {
    if (true) {
      echo "runme_ko: before"
      sh 'echo toto'
      echo "runme_ko: after"
    }
  }
}

There is a bug in my groovy library: MyParameters is not serializable.

The job fails because of that bug, but without printing a backtrace, which make the problem hard to find.

Here is the job output:

Started by user anonymous
Running: run_stage
Entering stage run_stage
Proceeding
Running: Allocate node : Start
Running on qisrc in /home/jenkins/jenkins/workspace/agility-next@4
Running: Allocate node : Body : Start
Running: Print Message
runme_ko: before
Running: Shell Script
[agility-next@4] Running shell script
Running: Allocate node : Body : End
Running: End of Workflow
Finished: FAILURE

Note that sometimes (when I modify the library, I think) a backtrace is printed.