Fix poll notifications reappearing after dismissal (#37948)

When a remote server sends ActivityPub Update activities for an
already-expired poll, queue_poll_notifications! would schedule a
PollExpirationNotifyWorker with a past timestamp, causing Sidekiq to
execute it immediately. If the user had already dismissed the
notification, a new one would be created, leading to an infinite loop.

Fix by adding an early return when the poll has already expired.

app/services/activitypub/process_status_update_service.rb

@@ -410,6 +410,11 @@ class ActivityPub::ProcessStatusUpdateService < BaseService
 
     return unless poll.present? && poll.expires_at.present? && poll.votes.exists?
 
+    # Do not schedule notifications for already-expired polls, as the
+    # notification worker would run immediately and re-create notifications
+    # that users may have already dismissed (see #37948)
+    return if poll.expired?
+
     PollExpirationNotifyWorker.remove_from_scheduled(poll.id) if @previous_expires_at.present? && @previous_expires_at > poll.expires_at
     PollExpirationNotifyWorker.perform_at(poll.expires_at + 5.minutes, poll.id)
   end

app/services/vote_service.rb

@@ -51,6 +51,10 @@ class VoteService < BaseService
   def queue_final_poll_check!
     return unless @poll.expires?
 
+    # Do not schedule if the poll has already expired, as the worker would
+    # run immediately and potentially re-create dismissed notifications (#37948)
+    return if @poll.expired?
+
     PollExpirationNotifyWorker.perform_at(@poll.expires_at + 5.minutes, @poll.id)
   end
 

spec/services/activitypub/process_status_update_service_spec.rb

@@ -136,6 +136,22 @@ RSpec.describe ActivityPub::ProcessStatusUpdateService do
       end
     end
 
+    context 'when the poll has already expired' do
+      let(:poll) { Fabricate(:poll, status: status, account: status.account, expires_at: 1.day.ago) }
+
+      before do
+        poll.votes.create!(account: Fabricate(:account, domain: nil), choice: 0)
+      end
+
+      it 'does not schedule a PollExpirationNotifyWorker' do
+        expect(PollExpirationNotifyWorker).to_not have_enqueued_sidekiq_job(poll.id)
+
+        subject.call(status, activity_json, object_json)
+
+        expect(PollExpirationNotifyWorker).to_not have_enqueued_sidekiq_job(poll.id)
+      end
+    end
+
     context 'when the status changes a poll despite being not explicitly marked as updated' do
       let(:account) { Fabricate(:account, domain: 'example.com') }
       let!(:expiration) { 10.days.from_now.utc }

spec/services/vote_service_spec.rb

@@ -24,6 +24,15 @@ RSpec.describe VoteService do
         end
       end
 
+      context 'when the remote poll has already expired' do
+        let(:poll) { Fabricate(:poll, account: account, options: %w(Foo Bar), expires_at: 1.day.ago) }
+
+        it 'does not schedule a PollExpirationNotifyWorker' do
+          expect { subject.call(voter, poll, [0]) }
+            .to_not change { PollExpirationNotifyWorker.jobs.size }
+        end
+      end
+
       context 'when the poll was created by a remote account' do
         let(:account) { Fabricate(:account, domain: 'host.example') }
 

spec/workers/poll_expiration_notify_worker_spec.rb

@@ -54,5 +54,23 @@ RSpec.describe PollExpirationNotifyWorker do
         end
       end
     end
+
+    context 'when a voter has already dismissed the notification' do
+      let(:voter) { Fabricate(:account, domain: nil) }
+      let(:poll) { Fabricate(:poll, account: status.account, status: status, expires_at: 1.day.ago) }
+
+      before do
+        poll.votes.create!(account: voter, choice: 0)
+        # First run creates the notification
+        described_class.new.perform(poll.id)
+        # User dismisses the notification
+        Notification.where(account: voter, activity: poll, type: :poll).destroy_all
+      end
+
+      it 'does not re-create the notification on a second run' do
+        expect { described_class.new.perform(poll.id) }
+          .to_not change { Notification.where(account: voter, activity: poll, type: :poll).count }.from(0)
+      end
+    end
   end
 end