Oh, I see the issue that I and christopheM are running into. The "copy artifacts from another project" specified by a "build parameter" only works when your parameter is the copy artifacts parameter. What we both need is for the "specific build" to be able to parse environment variables.

The copy artifact plugin even properly escapes environment variables. The issue is that the variable that the RunParameter creates is just the job URL. It also creates two other variables which contain the job name and number, but those are not valid variables (https://wiki.jenkins-ci.org/display/JENKINS/Parameterized+Build?focusedCommentId=58001926#comment-58001926). If those were valid we should be able to just use those.

I think there's some confusion on the purpose of the Run parameter.. it is for how to select a build, not about which project.. so this:

it defines a Run parameter (named "IFW") to select a build from the job "IFW"

is not possible. You simply define a build selector parameter named IFW and a default value.
When you add a Copy Artifact build step to the job you must specify the project to copy from (probably "IFW" in this case), and then for the build to select you can choose "from build parameter" and give "IFW" as the parameter name (using the name "IFW" for the build parameter is perhaps part of the confusion).

I just tried using a run parameter with Jenkins 1.461 and Copy Artifact 1.22, and didn't see any error. If you still see a problem, perhaps try in a different environment or setup and see if you can narrow down what factors cause the error.

oh, I was right there was confusion, but just now I figured out what it was... I see that "Run parameter" is one of the choices for the types of parameters you can add in a job, and indeed you can make one for picking a particular build from a particular project, like "IFW". Copy Artifact's "from build parameter" option does not support this type of parameter. It only supports the "Build selector for Copy Artifact" type of build parameter. You can select "specific build" here, but you have to type the build number.. you won't get a list of existing build numbers the way a "Run parameter" shows.

Closing. If you like you can file a feature request to support "Run parameter" for the build selector (though I have no plans to implement it).

How is this not a defect? The error message gives no indication of what was wrong or where to even start debugging the issue. Literally the best you can do is Google the message and hope that you find this bug. Google should be the last resort, not the only option.

+1 to Adam's comment, this is confusing and frustrating

using a "Build selector for Copy Artifact" parameter is not possible because it does not provide a way to select a build from another project (the upstream and downstream options are too restrictive)

a "Run parameter" makes the necessary selection possible, and should have been reused, but it seems it is not possible for Copy Artifacts to use that kind of parameter, I tried:

• "specified by a build parameter" ...already noted above doesn't work
• "specific build" and ${MY_RUN_PARAM_NAME} as the value ...doesn't work

I've opened a feature request here and will try and get a pull request ready
https://issues.jenkins-ci.org/browse/JENKINS-31569