diff --git a/danger/plugins/required_stops.rb b/danger/plugins/required_stops.rb
new file mode 100644
index 0000000000000000000000000000000000000000..7c845201d4dd4a734caa32d3d8004358ef4d3f50
--- /dev/null
+++ b/danger/plugins/required_stops.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+require_relative '../../tooling/danger/required_stops'
+
+module Danger
+ class RequiredStops < ::Danger::Plugin
+ # Put the helper code somewhere it can be tested
+ include Tooling::Danger::RequiredStops
+ end
+end
diff --git a/danger/required_stops/Dangerfile b/danger/required_stops/Dangerfile
new file mode 100644
index 0000000000000000000000000000000000000000..227ee0aa185013010f31ce9ca0c577f7ada3d791
--- /dev/null
+++ b/danger/required_stops/Dangerfile
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+required_stops.add_comment_for_finalized_migrations
diff --git a/spec/tooling/danger/required_stops_spec.rb b/spec/tooling/danger/required_stops_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..7a90f19ac094936eb2ed40a00b835713ca6b77b2
--- /dev/null
+++ b/spec/tooling/danger/required_stops_spec.rb
@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require 'gitlab-dangerfiles'
+require 'danger'
+require 'danger/plugins/internal/helper'
+require 'gitlab/dangerfiles/spec_helper'
+
+require_relative '../../../tooling/danger/required_stops'
+require_relative '../../../tooling/danger/project_helper'
+
+RSpec.describe Tooling::Danger::RequiredStops, feature_category: :tooling do
+ include_context "with dangerfile"
+
+ let(:fake_danger) { DangerSpecHelper.fake_danger.include(described_class) }
+ let(:fake_project_helper) { instance_double(Tooling::Danger::ProjectHelper) }
+ let(:warning_comment) { described_class::WARNING_COMMENT.chomp }
+
+ subject(:required_stops) { fake_danger.new(helper: fake_helper) }
+
+ before do
+ allow(required_stops).to receive(:project_helper).and_return(fake_project_helper)
+ end
+
+ describe '#add_comment_for_finalized_migrations' do
+ let(:file_lines) { file_diff.map { |line| line.delete_prefix('+').delete_prefix('-') } }
+
+ before do
+ allow(required_stops.project_helper).to receive(:file_lines).and_return(file_lines)
+ allow(required_stops.helper).to receive(:all_changed_files).and_return([filename])
+ allow(required_stops.helper).to receive(:changed_lines).with(filename).and_return(file_diff)
+ end
+
+ shared_examples "adds comment to added migration finalizations" do
+ context 'when model has a newly added migration finalization' do
+ let(:file_diff) do
+ [
+ "+ def up",
+ "+ finalize_background_migration(MIGRATION)",
+ "+ end",
+ "+ def up",
+ "+ finalize_background_migration('MyMigration')",
+ "+ end",
+ "+ def up",
+ "+ ensure_batched_background_migration_is_finished(",
+ "+ end",
+ "+ def up",
+ "+ ensure_batched_background_migration_is_finished('MyMigration')",
+ "+ end",
+ "+ def up",
+ "+ finalize_batched_background_migration(",
+ "+ end",
+ "+ def up",
+ "+ finalize_batched_background_migration('MyMigration')",
+ "+ end"
+ ]
+ end
+
+ it 'adds comment at the correct line' do
+ matching_line_numbers = [2, 5, 8, 11, 14, 17]
+ matching_line_numbers.each do |line_number|
+ expect(required_stops).to receive(:markdown).with("\n#{warning_comment}", file: filename, line: line_number)
+ end
+
+ required_stops.add_comment_for_finalized_migrations
+ end
+ end
+
+ context 'when model does not have migration finalization statement' do
+ let(:file_diff) do
+ [
+ "+ queue_batched_background_migration(",
+ "- ensure_batched_background_migration_is_finished("
+ ]
+ end
+
+ it 'does not add comment' do
+ expect(required_stops).not_to receive(:markdown)
+
+ required_stops.add_comment_for_finalized_migrations
+ end
+ end
+ end
+
+ context 'when model has a newly added migration finalization' do
+ context 'with regular migration' do
+ let(:filename) { 'db/migrate/my_migration.rb' }
+
+ include_examples 'adds comment to added migration finalizations'
+ end
+
+ context 'with post migration' do
+ let(:filename) { 'db/post_migrate/my_migration.rb' }
+
+ include_examples 'adds comment to added migration finalizations'
+ end
+ end
+ end
+end
diff --git a/tooling/danger/required_stops.rb b/tooling/danger/required_stops.rb
new file mode 100644
index 0000000000000000000000000000000000000000..dcba23021ad5e6510ca22ac230cd183b68086ffd
--- /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