Use linear version UserGroupNotificationSettingsFinder#execute

app/finders/user_group_notification_settings_finder.rb

@@ -8,7 +8,12 @@ class UserGroupNotificationSettingsFinder
 
   def execute
     # rubocop: disable CodeReuse/ActiveRecord
-    groups_with_ancestors = Gitlab::ObjectHierarchy.new(Group.where(id: groups.select(:id))).base_and_ancestors
+    selected_groups = Group.where(id: groups.select(:id))
+    groups_with_ancestors = if Feature.enabled?(:linear_user_group_notification_settings_finder_ancestors_scopes, user, default_enabled: :yaml)
+                              selected_groups.self_and_ancestors
+                            else
+                              Gitlab::ObjectHierarchy.new(selected_groups).base_and_ancestors
+                            end
     # rubocop: enable CodeReuse/ActiveRecord
 
     @loaded_groups_with_ancestors = groups_with_ancestors.index_by(&:id)

config/feature_flags/development/linear_user_group_notification_settings_finder_ancestors_scopes.yml

+---
+name: linear_user_group_notification_settings_finder_ancestors_scopes
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/74606
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/345792
+milestone: '14.6'
+type: development
+group: group::access
+default_enabled: false

spec/finders/user_group_notification_settings_finder_spec.rb

@@ -11,14 +11,15 @@ RSpec.describe UserGroupNotificationSettingsFinder do
     subject.map(&proc).uniq
   end
 
+  shared_examples 'user group notifications settings tests' do
     context 'when the groups have no existing notification settings' do
       context 'when the groups have no ancestors' do
         let_it_be(:groups) { create_list(:group, 3) }
 
         it 'will be a default Global notification setting', :aggregate_failures do
           expect(subject.count).to eq(3)
-        expect(attributes(&:notification_email)).to eq([nil])
-        expect(attributes(&:level)).to eq(['global'])
+          expect(attributes(&:notification_email)).to match_array([nil])
+          expect(attributes(&:level)).to match_array(['global'])
         end
       end
 
@@ -38,11 +39,11 @@ RSpec.describe UserGroupNotificationSettingsFinder do
           end
 
           it 'has the same level set' do
-          expect(attributes(&:level)).to eq(['participating'])
+            expect(attributes(&:level)).to match_array(['participating'])
           end
 
           it 'has the same email set' do
-          expect(attributes(&:notification_email)).to eq(['ancestor@example.com'])
+            expect(attributes(&:notification_email)).to match_array(['ancestor@example.com'])
           end
 
           it 'only returns the two queried groups' do
@@ -66,8 +67,8 @@ RSpec.describe UserGroupNotificationSettingsFinder do
 
           it 'has the same email and level set', :aggregate_failures do
             expect(subject.count).to eq(1)
-          expect(attributes(&:level)).to eq(['global'])
-          expect(attributes(&:notification_email)).to eq(['ancestor@example.com'])
+            expect(attributes(&:level)).to match_array(['global'])
+            expect(attributes(&:notification_email)).to match_array(['ancestor@example.com'])
           end
         end
 
@@ -82,8 +83,8 @@ RSpec.describe UserGroupNotificationSettingsFinder do
 
           it 'returns a default Global notification setting' do
             expect(subject.count).to eq(1)
-          expect(attributes(&:level)).to eq(['global'])
-          expect(attributes(&:notification_email)).to eq([nil])
+            expect(attributes(&:level)).to match_array(['global'])
+            expect(attributes(&:notification_email)).to match_array([nil])
           end
         end
 
@@ -103,8 +104,8 @@ RSpec.describe UserGroupNotificationSettingsFinder do
 
           it 'still inherits the notification settings' do
             expect(subject.count).to eq(1)
-          expect(attributes(&:level)).to eq(['participating'])
-          expect(attributes(&:notification_email)).to eq([ancestor_email.email])
+            expect(attributes(&:level)).to match_array(['participating'])
+            expect(attributes(&:notification_email)).to match_array([ancestor_email.email])
           end
         end
 
@@ -162,4 +163,15 @@ RSpec.describe UserGroupNotificationSettingsFinder do
         end
       end
     end
+  end
+
+  it_behaves_like 'user group notifications settings tests'
+
+  context 'when feature flag :linear_user_group_notification_settings_finder_ancestors_scopes is disabled' do
+    before do
+      stub_feature_flags(linear_user_group_notification_settings_finder_ancestors_scopes: false)
+    end
+
+    it_behaves_like 'user group notifications settings tests'
+  end
 end