Add API support for refreshing merge ref path

Add a merge_requests/:iid/merge_to_ref API which make
use of the groundwork to write merge results into
refs/merge-requests/:iid/merge.

1 files changed, 25 insertions, 0 deletions

diff --git a/lib/api/merge_requests.rb b/lib/api/merge_requests.rb
index 03f6684226f..44f1e81caf2 100644
--- a/lib/api/merge_requests.rb
+++ b/lib/api/merge_requests.rb
@@ -388,6 +388,31 @@ module API
         present merge_request, with: Entities::MergeRequest, current_user: current_user, project: user_project
       end
 
+      desc 'Merge a merge request to its default temporary merge ref path'
+      params do
+        optional :merge_commit_message, type: String, desc: 'Custom merge commit message'
+      end
+      put ':id/merge_requests/:merge_request_iid/merge_to_ref' do
+        merge_request = find_project_merge_request(params[:merge_request_iid])
+
+        authorize! :admin_merge_request, user_project
+
+        merge_params = {
+          commit_message: params[:merge_commit_message]
+        }
+
+        result = ::MergeRequests::MergeToRefService
+          .new(merge_request.target_project, current_user, merge_params)
+          .execute(merge_request)
+
+        if result[:status] == :success
+          present result.slice(:commit_id), 200
+        else
+          http_status = result[:http_status] || 400
+          render_api_error!(result[:message], http_status)
+        end
+      end
+
       desc 'Cancel merge if "Merge When Pipeline Succeeds" is enabled' do
         success Entities::MergeRequest
       end