The COPYARTIFACT_BUIL_NUMBER_ variable name does not preserve numbers in job names. It removes numbers from job names. For example, if the job is called martin-test1, then the variable name name is: COPYARTIFACT_BUILD_NUMBER_MARTIN_TEST_ (the number has been removed)
- create a job whose name has a number in it, e.g. martin-test1
- run the job once to create some artifacts, and archive them
- create another job whose purpose is to copy the artifacts from the first job
- in the build phase of the second job, print the environment variables, e.g. with env, and examine the COPYARTIFACT_BUILD_NUMBER_ variable name. It should be missing the numbers
This was tested in Jenkins 1.524, with version 1.27 of the Copy Artifacts plugin.