Handle Reactions Without Users When Sending Notifications (#5820)

* Add reaction's owner existence in the database

* Add test

app/services/notifications/reactions/send.rb

@@ -24,8 +24,8 @@ module Notifications
 
         reaction_siblings = Reaction.where(reactable_id: reaction.reactable_id, reactable_type: reaction.reactable_type).
           where.not(reactions: { user_id: reaction.reactable_user_id }).
-          includes(:reactable, :user).
-          order("created_at DESC")
+          preload(:reactable).includes(:user).where.not(users: { id: nil }).
+          order("reactions.created_at DESC")
 
         aggregated_reaction_siblings = reaction_siblings.map { |reaction| { category: reaction.category, created_at: reaction.created_at, user: user_data(reaction.user) } }
 

spec/models/notification_spec.rb

@@ -292,6 +292,18 @@ RSpec.describe Notification, type: :model do
           end
         end.to change(article.user.notifications, :count).by(1)
       end
+
+      it "does not send a notification to the author of an article if the reaction owner is deleted" do
+        user4 = create(:user)
+        reaction = create(:reaction, reactable: article, user: user4)
+        user4.delete
+
+        expect do
+          sidekiq_perform_enqueued_jobs do
+            described_class.send_reaction_notification(reaction, reaction.reactable.user)
+          end
+        end.not_to change(article.user.notifications, :count)
+      end
     end
 
     context "when a reaction is destroyed" do