Starting a promotion of a build in a specific branch of a multi-branch project gives an empty promotions page. There is no promotion possible.

Stepping back out to the parent multi-branch project and clicking the promotion icon gives a promotion rule unexpectedly. At this layer of a multi-branch project, the promotion plugin has no means of identifying which branch to promote. Running it anyways results in an attempt to promote artifacts from the parent project directory, resulting in an inability to find the artifacts and a traceback. Traceback attached. Promotion not working.

Workaround available: The promotion runs a shellscript that signs the artifact debian packages and pushes them to a repository. Manually running the script completes normally.

It would appear that the multi-branch plugin and the promotion plugin do not work together, as the promotion plugin is too brittle to handle $WORKSPACE being down one more directory level than in a single-branch project.