FIX: correctly notifies subscribers with post_action_destroyer (#16084)

lib/post_action_destroyer.rb

@@ -48,15 +48,29 @@ class PostActionDestroyer
 
     UserActionManager.post_action_destroyed(post_action)
     PostActionNotifier.post_action_deleted(post_action)
-
     result.success = true
     result.post = @post.reload
 
+    notify_subscribers
+
     result
   end
 
 protected
 
+  def self.notify_types
+    @notify_types ||= PostActionType.notify_flag_types.keys
+  end
+
+  def notify_subscribers
+    name = PostActionType.types[@post_action_type_id]
+    if name == :like
+      @post.publish_change_to_clients!(:liked, { likes_count: @post.like_count })
+    elsif self.class.notify_types.include?(name)
+      @post.publish_change_to_clients!(:acted)
+    end
+  end
+
   def guardian
     @guardian ||= Guardian.new(@destroyed_by)
   end

spec/lib/post_action_destroyer_spec.rb

@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+describe PostActionDestroyer do
+  fab!(:admin) { Fabricate(:admin) }
+  fab!(:user) { Fabricate(:user) }
+  fab!(:post) { Fabricate(:post) }
+
+  describe '#perform' do
+    context 'like' do
+      context 'post action exists' do
+        before do
+          PostActionCreator.new(user, post, PostActionType.types[:like]).perform
+        end
+
+        it 'destroys the post action' do
+          expect {
+            PostActionDestroyer.destroy(user, post, :like)
+          }.to change { PostAction.count }.by(-1)
+        end
+
+        it 'notifies subscribers' do
+          expect(post.reload.like_count).to eq(1)
+
+          messages = MessageBus.track_publish do
+            PostActionDestroyer.destroy(user, post, :like)
+          end
+
+          message = messages.last.data
+          expect(message[:type]).to eq(:liked)
+          expect(message[:likes_count]).to eq(0)
+        end
+      end
+
+      context 'post action doesn’t exist' do
+        describe 'perform' do
+          it 'fails' do
+            result = PostActionDestroyer.destroy(user, post, :like)
+            expect(result.success).to eq(false)
+            expect(result.not_found).to eq(true)
+          end
+        end
+      end
+    end
+
+    context 'any other notifiable type' do
+      before do
+        PostActionCreator.new(user, post, PostActionType.types[:spam]).perform
+      end
+
+      it 'destroys the post action' do
+        expect {
+          PostActionDestroyer.destroy(user, post, :spam)
+        }.to change { PostAction.count }.by(-1)
+      end
+
+      it 'notifies subscribers' do
+        messages = MessageBus.track_publish do
+          PostActionDestroyer.destroy(user, post, :spam)
+        end
+
+        expect(messages.last.data[:type]).to eq(:acted)
+      end
+    end
+
+    context 'not notifyable type' do
+      before do
+        PostActionCreator.new(user, post, PostActionType.types[:bookmark]).perform
+      end
+
+      it 'destroys the post action' do
+        expect {
+          PostActionDestroyer.destroy(user, post, :bookmark)
+        }.to change { PostAction.count }.by(-1)
+      end
+
+      it 'doesn’t notify subscribers' do
+        messages = MessageBus.track_publish do
+          PostActionDestroyer.destroy(user, post, :bookmark)
+        end
+
+        expect(messages).to be_blank
+      end
+    end
+  end
+end