jenkins groovy script to get the build result of a given build's upstream cause

getUpstreamTriggerBuildResult.groovy

import jenkins.model.Jenkins
import hudson.model.AbstractItem
import hudson.model.Cause

// === this code enables you to run this whole thing ===
// === just in https://myjenkins.me/script console   ===
def currentBuild = Jenkins.instance.getAllItems(AbstractItem.class)
  .findAll{ it.fullName == "my/org/job-name" }
  .collect{ it.builds.findAll{ it.number == 3 } } // desired build number of "my/org/job-name"
  .flatten()[0]
// =====================================================

// the below code can be used in a groovy script in a jenkins job because 'currentBuild' is available in context
Cause.UpstreamCause cause = currentBuild.getCause(Cause.UpstreamCause.class)

def upstreamTriggerBuildResult = Jenkins.instance.getAllItems(AbstractItem.class)
  .findAll{ it.fullName == cause.getUpstreamProject() }
  .collect{ proj -> proj.getBuilds().findAll{ it.number == cause.getUpstreamBuild() }.collect{ it.getResult() } }
  .flatten()[0]