MergeRequests::PushOptionsHandlerService has been updated to allow
creating and updating merge requests with the
`remove_source_branch` set using git push options.
To create a new merge request and set it to remove the source branch
when it is merged:
git push -u origin -o merge_request.create \
-o merge_request.remove_source_branch
To update an existing merge request and set it to remove the source
branch when it is merged:
git push -u origin -o merge_request.remove_source_branch
Issue https://gitlab.com/gitlab-org/gitlab-ce/issues/64320
