Fix Remove source-branch for MRs from same project

CHANGELOG

@@ -11,6 +11,7 @@ v 7.14.0 (unreleased)
   - Expire Rails cache entries after two weeks to prevent endless Redis growth
   - Add support for destroying project milestones (Stan Hu)
   - Add fetch command to the MR page.
+  - Fix bug causing "Remove source-branch" option not to work for merge requests from the same project.
 
 v 7.13.0 (unreleased)
   - Remove repository graph log to fix slow cache updates after push event (Stan Hu)

app/models/merge_request.rb

@@ -235,6 +235,10 @@ class MergeRequest < ActiveRecord::Base
       execute(self, commit_message)
   end
 
+  def remove_source_branch?
+    self.should_remove_source_branch && !self.source_project.root_ref?(self.source_branch) && !self.for_fork?
+  end
+
   def open?
     opened? || reopened?
   end

app/services/files/base_service.rb

@@ -39,7 +39,7 @@ module Files
 
     def after_commit(sha, branch)
       commit = repository.commit(sha)
-      full_ref = 'refs/heads/' + branch
+      full_ref = "#{Gitlab::Git::BRANCH_REF_PREFIX}#{branch}"
       old_sha = commit.parent_id || Gitlab::Git::BLANK_SHA
       GitPushService.new.execute(project, current_user, old_sha, sha, full_ref)
     end

app/services/merge_requests/auto_merge_service.rb

@@ -37,6 +37,10 @@ module MergeRequests
         # Merge local branches using rugged instead of satellites
         if sha = commit
           after_commit(sha, merge_request.target_branch)
+
+          if merge_request.remove_source_branch?
+            DeleteBranchService.new(merge_request.source_project, current_user).execute(merge_request.source_branch)
+          end
         end
       end
     end
@@ -55,7 +59,7 @@ module MergeRequests
 
     def after_commit(sha, branch)
       commit = repository.commit(sha)
-      full_ref = 'refs/heads/' + branch
+      full_ref = "#{Gitlab::Git::BRANCH_REF_PREFIX}#{branch}"
       old_sha = commit.parent_id || Gitlab::Git::BLANK_SHA
       GitPushService.new.execute(project, current_user, old_sha, sha, full_ref)
     end

lib/gitlab/satellite/merge_action.rb

@@ -33,7 +33,7 @@ module Gitlab
             merge_repo.git.push(default_options, :origin, merge_request.target_branch)
 
             # remove source branch
-            if merge_request.should_remove_source_branch && !project.root_ref?(merge_request.source_branch) && !merge_request.for_fork?
+            if merge_request.remove_source_branch?
               # will raise CommandFailed when push fails
               merge_repo.git.push(default_options, :origin, ":#{merge_request.source_branch}")
             end