Ignore removed queues in danger sidekiq_queues

lib/gitlab/danger/sidekiq_queues.rb

@@ -14,7 +14,7 @@ module Gitlab
       def changed_queue_names
         @changed_queue_names ||=
           (new_queues.values_at(*old_queues.keys) - old_queues.values)
-            .map { |queue| queue[:name] }
+            .compact.map { |queue| queue[:name] }
       end
 
       private

spec/lib/gitlab/danger/sidekiq_queues_spec.rb

@@ -62,5 +62,21 @@ RSpec.describe Gitlab::Danger::SidekiqQueues do
 
       expect(sidekiq_queues.changed_queue_names).to contain_exactly(:post_receive, :process_commit)
     end
+
+    it 'ignores removed queues' do
+      old_queues = {
+        merge: { name: :merge, urgency: :low },
+        post_receive: { name: :post_receive, urgency: :high }
+      }
+
+      new_queues = {
+        post_receive: { name: :post_receive, urgency: :low }
+      }
+
+      allow(sidekiq_queues).to receive(:old_queues).and_return(old_queues)
+      allow(sidekiq_queues).to receive(:new_queues).and_return(new_queues)
+
+      expect(sidekiq_queues.changed_queue_names).to contain_exactly(:post_receive)
+    end
   end
 end