Merge branch 'mc/backstage/make-pipelineupdateworker-idempotent' into 'master'

Make PipelineUpdateWorker idempotent

Closes #30585 and #216734

See merge request gitlab-org/gitlab!36010

app/workers/all_queues.yml

@@ -1018,7 +1018,7 @@
   :urgency: :high
   :resource_boundary: :unknown
   :weight: 5
-  :idempotent: 
+  :idempotent: true
   :tags: []
 - :name: pipeline_processing:stage_update
   :feature_category: :continuous_integration

app/workers/pipeline_update_worker.rb

 # frozen_string_literal: true
 
-class PipelineUpdateWorker # rubocop:disable Scalability/IdempotentWorker
+class PipelineUpdateWorker
   include ApplicationWorker
   include PipelineQueue
 
   queue_namespace :pipeline_processing
   urgency :high
 
+  idempotent!
+
   def perform(pipeline_id)
     Ci::Pipeline.find_by_id(pipeline_id)&.update_legacy_status
   end

spec/workers/pipeline_update_worker_spec.rb

@@ -12,6 +12,14 @@ RSpec.describe PipelineUpdateWorker do
 
         described_class.new.perform(pipeline.id)
       end
+
+      include_examples 'an idempotent worker' do
+        let(:job_args) { [pipeline.id] }
+
+        it 'sets pipeline status to skipped' do
+          expect { subject }.to change { pipeline.reload.status }.from('pending').to('skipped')
+        end
+      end
     end
 
     context 'when pipeline does not exist' do