Make the mergeability check worker idempotent

app/workers/all_queues.yml

@@ -1143,7 +1143,7 @@
   :urgency: :low
   :resource_boundary: :unknown
   :weight: 1
-  :idempotent: 
+  :idempotent: true
 - :name: migrate_external_diffs
   :feature_category: :source_code_management
   :has_external_dependencies: 

app/workers/merge_request_mergeability_check_worker.rb

 # frozen_string_literal: true
 
-class MergeRequestMergeabilityCheckWorker # rubocop:disable Scalability/IdempotentWorker
+class MergeRequestMergeabilityCheckWorker
   include ApplicationWorker
 
   feature_category :source_code_management
+  idempotent!
 
   def perform(merge_request_id)
     merge_request = MergeRequest.find_by_id(merge_request_id)

spec/workers/merge_request_mergeability_check_worker_spec.rb

@@ -25,5 +25,16 @@ describe MergeRequestMergeabilityCheckWorker do
         subject.perform(merge_request.id)
       end
     end
+
+    it_behaves_like 'an idempotent worker' do
+      let(:merge_request) { create(:merge_request) }
+      let(:job_args) { [merge_request.id] }
+
+      it 'is mergeable' do
+        subject
+
+        expect(merge_request).to be_mergeable
+      end
+    end
   end
 end