Support rm src branch on merge w/ push option

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

1 files changed, 14 insertions, 0 deletions

diff --git a/doc/user/project/merge_requests/index.md b/doc/user/project/merge_requests/index.md
index f593046fa8b..485ce9c351f 100644
--- a/doc/user/project/merge_requests/index.md
+++ b/doc/user/project/merge_requests/index.md
@@ -285,6 +285,7 @@ as pushing changes:
 - Create a new merge request for the pushed branch.
 - Set the target of the merge request to a particular branch.
 - Set the merge request to merge when its pipeline succeeds.
+- Set the merge request to remove the source branch when it's merged.
 
 ### Create a new merge request using git push options
 
@@ -328,6 +329,19 @@ pipeline succeeds at the same time using a `-o` flag per push option:
 git push -o merge_request.create -o merge_request.merge_when_pipeline_succeeds
 ```
 
+### Set removing the source branch using git push options
+
+To set an existing merge request to remove the source branch when the
+merge request is merged, the
+`merge_request.remove_source_branch` push option can be used:
+
+```sh
+git push -o merge_request.remove_source_branch
+```
+
+You can also use this push option in addition to the
+`merge_request.create` push option.
+
 ## Find the merge request that introduced a change
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/issues/2383) in GitLab 10.5.