1 files changed, 41 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/delete_conflicting_redirect_routes_range.rb b/lib/gitlab/background_migration/delete_conflicting_redirect_routes_range.rb
new file mode 100644
index 00000000000..b1411be3016
--- /dev/null
+++ b/lib/gitlab/background_migration/delete_conflicting_redirect_routes_range.rb
@@ -0,0 +1,41 @@
+module Gitlab
+  module BackgroundMigration
+    class DeleteConflictingRedirectRoutesRange
+      class Route < ActiveRecord::Base
+        self.table_name = 'routes'
+      end
+
+      class RedirectRoute < ActiveRecord::Base
+        self.table_name = 'redirect_routes'
+      end
+
+      # start_id - The start ID of the range of events to process
+      # end_id - The end ID of the range to process.
+      def perform(start_id, end_id)
+        return unless migrate?
+
+        conflicts = RedirectRoute.where(routes_match_redirects_clause(start_id, end_id))
+        num_rows = conflicts.delete_all
+
+        Rails.logger.info("Gitlab::BackgroundMigration::DeleteConflictingRedirectRoutesRange [#{start_id}, #{end_id}] - Deleted #{num_rows} redirect routes that were conflicting with routes.")
+      end
+
+      def migrate?
+        Route.table_exists? && RedirectRoute.table_exists?
+      end
+
+      def routes_match_redirects_clause(start_id, end_id)
+        <<~ROUTES_MATCH_REDIRECTS
+          EXISTS (
+            SELECT 1 FROM routes
+            WHERE (
+              LOWER(redirect_routes.path) = LOWER(routes.path)
+              OR LOWER(redirect_routes.path) LIKE LOWER(CONCAT(routes.path, '/%'))
+            )
+            AND routes.id BETWEEN #{start_id} AND #{end_id}
+          )
+        ROUTES_MATCH_REDIRECTS
+      end
+    end
+  end
+end