Add button to delete all merged branches

It adds a button to the branches page that the user can use to delete
all the branches that are already merged. This can be used to clean up
all the branches that were forgotten to delete while merging MRs.

Fixes #21076.

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/api/branches.rb b/lib/api/branches.rb
index 21a106387f0..73aed624ea7 100644
--- a/lib/api/branches.rb
+++ b/lib/api/branches.rb
@@ -128,6 +128,18 @@ module API
           render_api_error!(result[:message], result[:return_code])
         end
       end
+
+      # Delete all merged branches
+      #
+      # Parameters:
+      #   id (required) - The ID of a project
+      # Example Request:
+      #   DELETE /projects/:id/repository/branches/delete_merged
+      delete ":id/repository/merged_branches" do
+        DeleteMergedBranchesService.new(user_project, current_user).async_execute
+
+        status(200)
+      end
     end
   end
 end