Deleting builds from a job but not the promoted ones

Issue

You want to delete all builds from a job, but not the ones that were promoted.

Environment

CloudBees CI (CloudBees Core) on modern cloud platforms - Managed controller
CloudBees CI (CloudBees Core) on traditional platforms - Client controller
CloudBees Jenkins Enterprise - Managed controller
Jenkins LTS

Resolution

The following script run in the Jenkins script console at Manage Jenkins » Script Console does that. Note that you should always make sure to have good backups before deleting things like this in a script.

Jenkins.instance.getItemByFullName("yourJobNameHere").builds.each {
  def p = it.getAction(hudson.plugins.promoted_builds.PromotedBuildAction)
  if (!p || !p.hasPromotion()) {
    it.delete()
  }
}
return

Replace "yourJobNameHere" with the name of the job.