It is not work with Blue Ocean 1.19.0

For anybody struggling with this and in need of some inspiration for a workaround, we are using a wrapper for the job step which prints a link to the downstream build until this issue is fixed. Better than nothing:

def getBlueOceanLink(obj, jobName) {
  def buildNumber

  if(obj instanceof Exception) {
    obj.toString().split(" ").each {
      if(it.contains("#")) {
        buildNumber = it.substring(1)
      }
    }
  } else if(obj instanceof org.jenkinsci.plugins.workflow.support.steps.build.RunWrapper) {
    buildNumber = obj.getNumber()
  } else {
    return "Can not determine Blue Ocean link!!!"
  }

  return "For detailed information see: http://<YOUR JENKINS>/blue/organizations/jenkins/${jobName}/detail/${jobName}/${buildNumber}/pipeline"
}

// Wrapper:
def linkBuild(job, parameters) {
    def buildInfo
    try {
        buildInfo = build(job: job, parameters: parameters, wait: true, propagate: true)
    } catch (Exception e) {
        println getBlueOceanLink(e, job)
        throw e
    }
    println getBlueOceanLink(buildInfo, job)
}

// Usage:
stage ("My stage") {
 linkBuild("My job", [
  string(name: "my param", value: some_value)
 ])
}

If anybody has come up with something better I would love to hear it!

I have raised a bug for this JENKINS-60995

as it is a regression of existing functionality 

Sometimes it works. but not always. For some reasons the NodeDownstreamBuildAction is missing when using the api /blue/rest/organizations/jenkins/pipelines/

When going closer into /blue/rest/organizations/jenkins/pipelines/<project>/runs/x/nodes/y/ the information is missing in this endpoint too.

Funny fact, I've debugged it with the Script console by replaying the code from https://github.com/jenkinsci/blueocean-plugin/blob/master/blueocean-pipeline-api-impl/src/main/java/io/jenkins/blueocean/listeners/DownstreamJobListener.java. This works and all the triggered builds are there.

But for me it's too complex to dig into the blue-ocean rest and debug there.

Any suggestion from anyone how to debug it?

I've been looking into this as well. What I've found so far:

• The downstream runs have an associated BuildUpstreamNodeAction contributed by the build step.
• The BuildUpstreamNodeAction action has an upstreamNodeId pointing back to the build step that triggered the downstream run.
• This DownstreamJobListener adds a NodeDownstreamBuildAction to the node pointed to by the upstreamNodeId.
• This upstreamNodeId doesn't match the id of the node typically selected when viewing the Blue Ocean pipeline graph (that node is typically a stage or parallel branch node)
• There's code in PipelineNodeGraphVisitor.java that accumulates actions from nodes within a branch or stage and then adds them to the node for that branch or stage. I believe this is the source of the issue.