FIX: do not validate topic deletions

lib/post_destroyer.rb

@@ -168,12 +168,12 @@ class PostDestroyer
 
   def make_previous_post_the_last_one
     last_post = Post.where("topic_id = ? and id <> ?", @post.topic_id, @post.id).order('created_at desc').limit(1).first
-    if last_post.present?
-      @post.topic.update!(
-        last_posted_at: last_post.created_at,
-        last_post_user_id: last_post.user_id,
-        highest_post_number: last_post.post_number
-      )
+    if last_post.present? && @post.topic.present?
+      topic = @post.topic
+      topic.last_posted_at = last_post.created_at
+      topic.last_post_user_id = last_post.user_id
+      topic.highest_post_number = last_post.post_number
+      topic.save!(validate: false)
     end
   end
 

spec/components/post_destroyer_spec.rb

@@ -265,9 +265,10 @@ describe PostDestroyer do
     end
 
     it "when topic is destroyed, it updates user_stats correctly" do
-      post
+      SiteSetting.min_topic_title_length = 5
+      post.topic.update_column(:title, "xyz")
+
       user1 = post.user
-      user1.reload
       user2 = Fabricate(:user)
       reply = create_post(topic_id: post.topic_id, user: user2)
       reply2 = create_post(topic_id: post.topic_id, user: user1)
@@ -275,6 +276,7 @@ describe PostDestroyer do
       expect(user1.user_stat.post_count).to eq(1)
       expect(user2.user_stat.topic_count).to eq(0)
       expect(user2.user_stat.post_count).to eq(1)
+
       PostDestroyer.new(Fabricate(:admin), post).destroy
       user1.reload
       user2.reload
@@ -390,12 +392,13 @@ describe PostDestroyer do
 
     let(:user) { Fabricate(:user) }
     let!(:post) { create_post(user: user) }
-    let(:topic) { post.topic.reload }
+    let(:topic) { post.topic }
     let(:second_user) { Fabricate(:coding_horror) }
     let!(:second_post) { create_post(topic: topic, user: second_user) }
 
     before do
       PostDestroyer.new(moderator, second_post).destroy
+      topic.reload
     end
 
     it 'resets the last_poster_id back to the OP' do
@@ -406,6 +409,10 @@ describe PostDestroyer do
       expect(topic.last_posted_at.to_i).to eq(post.created_at.to_i)
     end
 
+    it 'resets the highest_post_number' do
+      expect(topic.highest_post_number).to eq(post.post_number)
+    end
+
     context 'topic_user' do
 
       let(:topic_user) { second_user.topic_users.find_by(topic_id: topic.id) }
@@ -421,9 +428,7 @@ describe PostDestroyer do
       it "sets the second user's last_read_post_number back to 1" do
         expect(topic_user.highest_seen_post_number).to eq(1)
       end
-
     end
-
   end
 
   context "deleting a post belonging to a deleted topic" do