grab highest post number from the raw data, so deletions at the end of a topic work

app/serializers/topic_view_serializer.rb

@@ -5,7 +5,6 @@ class TopicViewSerializer < ApplicationSerializer
     [:id,
      :title,
      :posts_count,
-     :highest_post_number,
      :created_at,
      :views,
      :reply_count,
@@ -41,7 +40,8 @@ class TopicViewSerializer < ApplicationSerializer
              :notification_level,
              :notifications_reason_id,
              :posts,
-             :at_bottom
+             :at_bottom,
+             :highest_post_number
 
   has_one :created_by, serializer: BasicUserSerializer, embed: :objects
   has_one :last_poster, serializer: BasicUserSerializer, embed: :objects
@@ -185,7 +185,11 @@ class TopicViewSerializer < ApplicationSerializer
 
   # Whether we're at the bottom of a topic (last page)
   def at_bottom
-    posts.present? and (@highest_number_in_posts == object.topic.highest_post_number)
+    posts.present? and (@highest_number_in_posts == object.highest_post_number)
+  end
+
+  def highest_post_number
+    object.highest_post_number
   end
 
   def posts

lib/topic_view.rb

@@ -223,6 +223,15 @@ class TopicView
     @suggested_topics ||= TopicQuery.new(@user).list_suggested_for(topic)
   end
 
+  # This is pending a larger refactor, that allows custom orders
+  #  for now we need to look for the highest_post_number in the stream 
+  #  the cache on topics is not correct if there are deleted posts at 
+  #  the end of the stream (for mods), nor is it correct for filtered 
+  #  streams
+  def highest_post_number
+    @highest_post_number ||= @posts.maximum(:post_number)
+  end
+
   protected
 
   def read_posts_set

spec/components/topic_view_spec.rb

@@ -106,10 +106,12 @@ describe TopicView do
   end
 
   it 'allows admins to see deleted posts' do 
+    post_number = p3.post_number
     p3.destroy
     admin = Fabricate(:admin)
     topic_view = TopicView.new(topic.id, admin) 
     topic_view.posts.count.should == 3
+    topic_view.highest_post_number.should == post_number
   end
   
   it 'does not allow non admins to see deleted posts' do 
@@ -117,7 +119,7 @@ describe TopicView do
     topic_view.posts.count.should == 2
   end
 
-  # Sam: disabled for now, we only need this for poss, if we do, roll it into topic
+  # Sam: disabled for now, we only need this for polls, if we do, roll it into topic
   #  having to walk every post action is not really a good idea
   #
   # context '.voted_in_topic?' do