Support variable expansion in branch property of trigger keyword
We want to avoid spawning an actual CI job on CI runner just to execute cURL to trigger downstream pipelines which bridge jobs should allow us to do.
But we maintain several branches in parallel and want to propagate the correct branch into the downstream pipeline, e.g. a
master build in the upstream project should trigger a
master build in the downstream project whereas a build of
release-v1.0 upstream should trigger
We naively tried to accomplish this using a bridge job with
trigger: project: downstream/project branch: $CI_COMMIT_REF_NAME
as we did use
--form "ref=$CI_COMMIT_REF_NAME" as a command line argument to
curl before. But this does not work as variables are not expanded in the
branch parameter and hence the bridge job fails as no ref named
$CI_COMMIT_REF_NAME exists in the downstream repository.