Advance Search: Merge request with labels

EE: true

ee/config/feature_flags/gitlab_com_derisk/search_mr_filter_label_ids.yml

+---
+name: search_mr_filter_label_ids
+feature_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/464090
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/160425
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/473796
+milestone: '17.3'
+group: group::global search
+type: gitlab_com_derisk
+default_enabled: false

ee/lib/gitlab/elastic/search_results.rb

@@ -326,9 +326,9 @@ def scope_options(scope)
         when :projects, :notes, :commits
           base_options.merge(filters.slice(:include_archived))
         when :merge_requests
-          base_options
-            .merge(filters.slice(:order_by, :sort, :state, :include_archived, :source_branch, :not_source_branch,
-              :author_username, :not_author_username))
+          base_options.merge(
+            filters.slice(:order_by, :sort, :state, :include_archived, :source_branch, :not_source_branch,
+              :author_username, :not_author_username, :label_name))
         when :issues
           base_options.merge(
             filters.slice(:order_by, :sort, :confidential, :state, :labels, :label_name, :include_archived),

ee/lib/search/elastic/merge_request_query_builder.rb

@@ -40,6 +40,11 @@ def build
           query_hash = ::Search::Elastic::Filters.by_not_hidden(query_hash: query_hash, options: options)
         end
 
+        if Feature.enabled?(:search_mr_filter_label_ids, options[:current_user]) &&
+            ::Elastic::DataMigrationService.migration_has_finished?(:reindex_merge_requests_to_backfill_label_ids)
+          query_hash = ::Search::Elastic::Filters.by_label_ids(query_hash: query_hash, options: options)
+        end
+
         query_hash = ::Search::Elastic::Formats.source_fields(query_hash: query_hash, options: options)
         query_hash = ::Search::Elastic::Formats.size(query_hash: query_hash, options: options)
 

ee/spec/lib/search/elastic/merge_request_query_builder_spec.rb

@@ -181,6 +181,54 @@
         end
       end
     end
+
+    describe 'labels' do
+      let_it_be(:label) { create(:label, project: authorized_project) }
+
+      before do
+        set_elasticsearch_migration_to(:reindex_merge_requests_to_backfill_label_ids, including: true)
+      end
+
+      context 'when search_mr_filter_label_ids flag is false' do
+        before do
+          stub_feature_flags(search_mr_filter_label_ids: false)
+        end
+
+        it 'does not include labels filter by default' do
+          assert_names_in_query(build, without: %w[filters:label_ids])
+        end
+
+        context 'when label_name option is provided' do
+          let(:options) { base_options.merge(label_name: [label.name]) }
+
+          it 'does not include labels filter' do
+            assert_names_in_query(build, without: %w[filters:label_ids])
+          end
+        end
+      end
+
+      it 'does not include labels filter by default' do
+        assert_names_in_query(build, without: %w[filters:label_ids])
+      end
+
+      context 'when label_name option is provided' do
+        let(:options) { base_options.merge(label_name: [label.name]) }
+
+        it 'applies label filters' do
+          assert_names_in_query(build, with: %w[filters:label_ids])
+        end
+
+        context 'when the migration is not finished' do
+          before do
+            set_elasticsearch_migration_to(:reindex_merge_requests_to_backfill_label_ids, including: false)
+          end
+
+          it 'does not include labels filter' do
+            assert_names_in_query(build, without: %w[filters:label_ids])
+          end
+        end
+      end
+    end
   end
 
   it_behaves_like 'a sorted query'