Mark ProcessAlertWorkerV2 as idempotent

app/workers/all_queues.yml

@@ -1054,7 +1054,7 @@
   :urgency: :low
   :resource_boundary: :unknown
   :weight: 2
-  :idempotent:
+  :idempotent: true
   :tags: []
 - :name: incident_management:incident_management_process_prometheus_alert
   :worker_name: IncidentManagement::ProcessPrometheusAlertWorker

app/workers/incident_management/process_alert_worker_v2.rb

@@ -7,6 +7,8 @@ module IncidentManagement
     queue_namespace :incident_management
     feature_category :incident_management
 
+    idempotent!
+
     def perform(alert_id)
       return unless alert_id
 

spec/workers/incident_management/process_alert_worker_v2_spec.rb

@@ -42,6 +42,14 @@ RSpec.describe IncidentManagement::ProcessAlertWorkerV2 do
 
         expect(Gitlab::AppLogger).not_to have_received(:warn)
       end
+
+      it_behaves_like 'an idempotent worker' do
+        let(:job_args) { [alert.id] }
+
+        it 'does not create a second issue' do
+          expect { perform_worker }.to change { Issue.count }.by(1)
+        end
+      end
     end
 
     context 'with valid alert' do