Fix deletion of posts quoting soft-deleted local post (#36461)

app/services/revoke_quote_service.rb

@@ -21,6 +21,11 @@ class RevokeQuoteService < BaseService
   end
 
   def distribute_stamp_deletion!
+    # It is possible the quoted status has been soft-deleted.
+    # In this case, `signed_activity_json` would fail, but we can just ignore
+    # that, as we have already federated deletion.
+    return if @quote.quoted_status.nil?
+
     ActivityPub::DeliveryWorker.push_bulk(inboxes, limit: 1_000) do |inbox_url|
       [signed_activity_json, @account.id, inbox_url]
     end

spec/services/remove_status_service_spec.rb

@@ -129,4 +129,20 @@ RSpec.describe RemoveStatusService, :inline_jobs do
       )
     )
   end
+
+  context 'when removed status is a quote of a local user', inline_jobs: false do
+    let(:original_status) { Fabricate(:status, account: alice) }
+    let(:status) { Fabricate(:status, account: jeff) }
+
+    before do
+      bill.follow!(jeff)
+      Fabricate(:quote, status: status, quoted_status: original_status, state: :accepted)
+      original_status.discard
+    end
+
+    it 'sends deletion without crashing' do
+      expect { subject.call(status.reload) }
+        .to enqueue_sidekiq_job(ActivityPub::DeliveryWorker).with(/Delete/, jeff.id, bill.inbox_url)
+    end
+  end
 end