Merge branch 'n-plus-one-notification-recipients' into 'master'

Fix some N+1s when calculating notification recipients

Closes #45534

See merge request gitlab-org/gitlab-ce!19535

1 files changed, 36 insertions, 0 deletions

diff --git a/spec/services/notification_recipient_service_spec.rb b/spec/services/notification_recipient_service_spec.rb
new file mode 100644
index 00000000000..340d4585e0c
--- /dev/null
+++ b/spec/services/notification_recipient_service_spec.rb
@@ -0,0 +1,36 @@
+require 'spec_helper'
+
+describe NotificationRecipientService do
+  let(:service) { described_class }
+  let(:assignee) { create(:user) }
+  let(:project) { create(:project, :public) }
+  let(:other_projects) { create_list(:project, 5, :public) }
+
+  describe '#build_new_note_recipients' do
+    let(:issue) { create(:issue, project: project, assignees: [assignee]) }
+    let(:note) { create(:note_on_issue, noteable: issue, project_id: issue.project_id) }
+
+    def create_watcher
+      watcher = create(:user)
+      create(:notification_setting, project: project, user: watcher, level: :watch)
+
+      other_projects.each do |other_project|
+        create(:notification_setting, project: other_project, user: watcher, level: :watch)
+      end
+    end
+
+    it 'avoids N+1 queries' do
+      create_watcher
+
+      service.build_new_note_recipients(note)
+
+      control_count = ActiveRecord::QueryRecorder.new do
+        service.build_new_note_recipients(note)
+      end
+
+      create_watcher
+
+      expect { service.build_new_note_recipients(note) }.not_to exceed_query_limit(control_count)
+    end
+  end
+end