You can see my question on Stack Overflow (I probably should have posted here first).  https://stackoverflow.com/questions/62998712/i-am-unable-to-get-the-jenkins-copyartifact-plugin-with-the-specified-by-a-buil
 
I am having a hard time figuring out how to get the Jenkins CopyArtifact Plugin to work in the "Specified by a build Parameter" working.  I figured I could pass in a parameter somehow and filter on that parameter. The artifacts are created successfully, but I can't figure out how to specify the parameter to copy the artifact from.

I have been able to get copyArtifact with the "Latest Successful build" option running, so I know I have the permissions set right and the artifact and parameters are set as I expect.

I have 3 tasks (ztest1, ztest2, ztest3).

ztest1:

• triggers ztest2 (non-blocking) with a Parameter "START_BUILD_NUMBER"=${BUILD_NUMBER}
• sleep 10 seconds
• tries to copy the artifact from ztest3 

ztest2:

• takes the input parameter (START_BUILD_NUMBER) and triggers ztest3 (non-blocking) with a parameter "START_BUILD_NUMBER"=${START_BUILD_NUMBER}

ztest3: (I've tried a bunch of different things, but here's my current try)

• Take the "START_BUILD_NUMBER" and then create a second artifact "BUILD_TOKEN" that utilizes the "START_BUILD_NUMBER"
• 
• create the artifact
•  {{echo "ztest START_BUILD_NUMBER ${START_BUILD_NUMBER}" > test.txt
  echo "ztest3 BUILD_NUMBER ${BUILD_NUMBER}" >> test.txt
  echo "ztest BUILD_TOKEN ${BUILD_TOKEN}" >> test.txt}}

Am I missing anything: My actual use case is a bit more complicated, but this is the simple form that I was trying to use. My actual use case involves an asynchronous process between steps 2 and 3 and multiple entry points, Specifically step 2 can be fired separately, and then don't need to copy the artifact.

If I have to move to Groovy and a pipeline task, that is fine, but I can't get that to work either.