1 files changed, 41 insertions, 0 deletions
diff --git a/tooling/danger/required_stops.rb b/tooling/danger/required_stops.rb
new file mode 100644
index 00000000000..dcba23021ad
--- /dev/null
+++ b/tooling/danger/required_stops.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require_relative 'suggestor'
+
+module Tooling
+  module Danger
+    module RequiredStops
+      include ::Tooling::Danger::Suggestor
+
+      MIGRATION_FILES_REGEX = %r{^db/(post_)?migrate}
+
+      MIGRATION_FINALIZE_METHODS = %w[finalize_background_migration ensure_batched_background_migration_is_finished
+        finalize_batched_background_migration].freeze
+      MIGRATION_FINALIZE_REGEX = /^\+\s*(.*\.)?(#{MIGRATION_FINALIZE_METHODS.join('|')})[( ]/
+
+      DOC_URL = "https://docs.gitlab.com/ee/development/database/required_stops.html"
+      WARNING_COMMENT = <<~COMMENT.freeze
+        Finalizing data migration might be time consuming and require a [required stop](#{DOC_URL}).
+        Check the timings of the underlying data migration.
+        If possible postpone the finalization to the scheduled required stop.
+        If postponing is impossible please create new required stop as documentation suggests.
+      COMMENT
+
+      def add_comment_for_finalized_migrations
+        migration_files.each do |filename|
+          add_suggestion(
+            filename: filename,
+            regex: MIGRATION_FINALIZE_REGEX,
+            comment_text: WARNING_COMMENT
+          )
+        end
+      end
+
+      private
+
+      def migration_files
+        helper.all_changed_files.grep(MIGRATION_FILES_REGEX)
+      end
+    end
+  end
+end