Add ClickHouse review in Danger

- Mention group
- Label support

danger/database/clickhouse/Dangerfile

+# frozen_string_literal: true
+
+CH_MESSAGE = <<~MSG
+This merge request requires a ClickHouse review. To make sure these
+changes are reviewed, take the following steps:
+
+1. Ensure the merge request has ~clickhouse and ~"clickhouse::review pending" labels.
+1. Assign and mention a ClickHouse reviewer.
+MSG
+
+CH_UNREVIEWED_LABEL = 'clickhouse::review pending'
+CH_APPROVED_LABEL = 'clickhouse::approved'
+
+return if stable_branch.valid_stable_branch?
+return if helper.mr_labels.include?(CH_UNREVIEWED_LABEL)
+
+if helper.mr_labels.include?('clickhouse') || clickhouse.changes.any?
+  message 'This merge request adds or changes files that require a ' \
+          'review from the [GitLab ClickHouse team](https://gitlab.com/groups/gl-clickhouse/-/group_members).'
+
+  markdown(CH_MESSAGE)
+
+  helper.labels_to_add << CH_UNREVIEWED_LABEL unless helper.has_scoped_label_with_scope?("clickhouse")
+end

spec/tooling/danger/clickhouse_spec.rb

+# frozen_string_literal: true
+
+require 'rspec-parameterized'
+require 'gitlab-dangerfiles'
+require 'danger'
+require 'danger/plugins/internal/helper'
+require 'gitlab/dangerfiles/spec_helper'
+
+require_relative '../../../tooling/danger/clickhouse'
+
+RSpec.describe Tooling::Danger::Clickhouse, feature_category: :tooling do
+  include_context "with dangerfile"
+
+  let(:fake_danger) { DangerSpecHelper.fake_danger.include(described_class) }
+  let(:migration_files) do
+    %w[
+      db/click_house/20220901010203_add_widgets_table.rb
+      db/click_house/20220909010203_add_properties_column.rb
+      db/click_house/20220910010203_drop_tools_table.rb
+      db/click_house/20220912010203_add_index_to_widgets_table.rb
+    ]
+  end
+
+  subject(:clickhouse) { fake_danger.new(helper: fake_helper) }
+
+  describe '#changes' do
+    using RSpec::Parameterized::TableSyntax
+
+    where do
+      {
+        'with click_house gem changes' => {
+          modified_files: %w[gems/click_house-client/lib/click_house/client.rb],
+          changes_by_category: {
+            database: [],
+            clickhouse: %w[gems/click_house-client/lib/click_house/client.rb]
+          },
+          impacted_files: %w[gems/click_house-client/lib/click_house/client.rb]
+        },
+        'with clickhouse data changes' => {
+          modified_files: %w[db/clickhouse/20230720114001_add_magic_table_migration.rb],
+          changes_by_category: {
+            database: [],
+            clickhouse: %w[db/clickhouse/20230720114001_add_magic_table_migration.rb]
+          },
+          impacted_files: %w[db/clickhouse/20230720114001_add_magic_table_migration.rb]
+        },
+        'with clickhouse app changes' => {
+          modified_files: %w[lib/click_house/query_builder.rb],
+          changes_by_category: {
+            database: [],
+            clickhouse: %w[lib/click_house/query_builder.rb]
+          },
+          impacted_files: %w[lib/click_house/query_builder.rb]
+        }
+      }
+    end
+
+    with_them do
+      before do
+        allow(fake_helper).to receive(:modified_files).and_return(modified_files)
+        allow(fake_helper).to receive(:all_changed_files).and_return(modified_files)
+        allow(fake_helper).to receive(:changes_by_category).and_return(changes_by_category)
+      end
+
+      it 'returns only clickhouse changes' do
+        expect(clickhouse.changes).to match impacted_files
+      end
+    end
+  end
+end

tooling/danger/clickhouse.rb

+# frozen_string_literal: true
+
+module Tooling
+  module Danger
+    module Clickhouse
+      def changes
+        helper.changes_by_category[:clickhouse]
+      end
+    end
+  end
+end

tooling/danger/project_helper.rb

@@ -106,6 +106,10 @@ module ProjectHelper
         %r{\A((ee|jh)/)?app/finders/} => [:database, :backend],
         %r{\Arubocop/cop/migration(/|\.rb)} => :database,
+        %r{\A(ee/)?db/click_house/} => :clickhouse,
+        %r{\Agems/click_house-client/} => :clickhouse,
+        %r{click(-)?house} => :clickhouse,
+
         %r{\Alib/gitlab/ci/templates} => :ci_template,
         %r{\A((ee|jh)/)?spec/features/} => :test,