If somehow a user attempted to accept a merge request that had
conflicts (e.g. the "Accept Merge Request" button or the MR itself was
not updated), `MergeService` did not properly detect that a conflict
occurred. It would assume that the MR went through without any issues
and close the MR as though everything was fine. This could cause
data loss if the source branch were removed.
Closes#20425
1. When a merge request is being merged, save the merge commit SHA in
the `in_progress_merge_commit_sha` database column.
2. The `pre-receive` hook looks for any locked (in progress) merge
request with `in_progress_merge_commit_sha` matching the `newrev` it
is passed.
3. If it finds a matching MR, the merge is legitimate.
4. Update `git_access_spec` to test the behaviour we added here. Also
refactored this spec a bit to make it easier to add more contexts / conditions.
Change "+" icon under "Files" section to have three options:
* Create file
* Upload file
* New directory
Upload file is no longer accessible from the "Create file" page.
Users can now select a target branch in upload file as well.
Closes#2799: Fixes a bug where file modes were overwritten after a commit
Closes https://github.com/gitlabhq/gitlabhq/issues/8253: Existing files
can no longer be overwritten in the "Create file" section.
Closes#2557
