FEATURE: when a post is deleted because a moderator agreed with flags, send a message to the post author

config/locales/server.en.yml

@@ -2241,6 +2241,20 @@ en:
 
         For additional guidance, please refer to our [community guidelines](%{base_url}/guidelines).
 
+    flags_agreed_and_post_deleted:
+      title: "Post deleted by a moderator"
+      subject_template: "Post deleted by a moderator due to flags"
+      text_body_template: |
+        Hello,
+
+        This is an automated message from %{site_name} to let you know that your post was deleted.
+
+        <%{base_url}%{url}>
+
+        A moderator reviewed flags submitted by the community and agreed with them.
+
+        Please review our [community guidelines](%{base_url}/guidelines) to avoid this happening again in the future.
+
     usage_tips:
       text_body_template: |
         For a few quick tips on getting started as a new user, [check out this blog post](https://blog.discourse.org/2016/12/discourse-new-user-tips-and-tricks/).

lib/post_destroyer.rb

@@ -196,6 +196,15 @@ class PostDestroyer
   end
 
   def agree_with_flags
+    if @post.is_flagged?
+      Jobs.enqueue(
+        :send_system_message,
+        user_id: @post.user.id,
+        message_type: :flags_agreed_and_post_deleted,
+        message_options: { url: @post.url }
+      )
+    end
+
     PostAction.agree_flags!(@post, @user, delete_post: true)
   end
 

spec/components/post_destroyer_spec.rb

@@ -567,6 +567,8 @@ describe PostDestroyer do
     let!(:flag) { PostAction.act(moderator, second_post, PostActionType.types[:off_topic]) }
 
     it "should delete public post actions and agree with flags" do
+      SiteSetting.queue_jobs = false
+
       second_post.expects(:update_flagged_posts_count)
 
       PostDestroyer.new(moderator, second_post).destroy
@@ -580,6 +582,10 @@ describe PostDestroyer do
       second_post.reload
       expect(second_post.bookmark_count).to eq(0)
       expect(second_post.off_topic_count).to eq(1)
+
+      notification = second_post.user.notifications.where(notification_type: Notification.types[:private_message]).last
+      expect(notification).to be_present
+      expect(notification.topic.title).to eq(I18n.t('system_messages.flags_agreed_and_post_deleted.subject_template'))
     end
   end
 

spec/models/post_action_spec.rb

@@ -233,6 +233,19 @@ describe PostAction do
     end
   end
 
+  describe "undo/redo repeatedly" do
+    it "doesn't create a second action for the same user/type" do
+      PostAction.act(codinghorror, post, PostActionType.types[:like])
+      PostAction.remove_act(codinghorror, post, PostActionType.types[:like])
+      PostAction.act(codinghorror, post, PostActionType.types[:like])
+      expect(PostAction.where(post: post).with_deleted.count).to eq(1)
+      PostAction.remove_act(codinghorror, post, PostActionType.types[:like])
+
+      # Check that we don't lose consistency into negatives
+      expect(post.reload.like_count).to eq(0)
+    end
+  end
+
   describe 'when a user likes something' do
 
     it 'should generate notifications correctly' do
@@ -307,22 +320,7 @@ describe PostAction do
         expect(actual_count).to eq(1), "Expected likes_given to be 1 when removing '#{type_name}', but got #{actual_count}"
       end
     end
-  end
 
-  describe "undo/redo repeatedly" do
-    it "doesn't create a second action for the same user/type" do
-      PostAction.act(codinghorror, post, PostActionType.types[:like])
-      PostAction.remove_act(codinghorror, post, PostActionType.types[:like])
-      PostAction.act(codinghorror, post, PostActionType.types[:like])
-      expect(PostAction.where(post: post).with_deleted.count).to eq(1)
-      PostAction.remove_act(codinghorror, post, PostActionType.types[:like])
-
-      # Check that we don't lose consistency into negatives
-      expect(post.reload.like_count).to eq(0)
-    end
-  end
-
-  describe 'when a user likes something' do
     it 'should increase the like counts when a user votes' do
       expect {
         PostAction.act(codinghorror, post, PostActionType.types[:like])