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)

To reproduce:

1. create a job whose name has a number in it, e.g. martin-test1
2. run the job once to create some artifacts, and archive them
3. create another job whose purpose is to copy the artifacts from the first job
4. 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.