FIX: actually retrieve the first 2 posts in a conversation about a flag

app/models/topic.rb

@@ -76,6 +76,7 @@ class Topic < ActiveRecord::Base
 
   belongs_to :category
   has_many :posts
+  has_many :ordered_posts, -> { order(post_number: :asc) }, class_name: "Post"
   has_many :topic_allowed_users
   has_many :topic_allowed_groups
 

lib/flag_query.rb

@@ -42,7 +42,7 @@ module FlagQuery
     end
 
     post_actions = actions.order('post_actions.created_at DESC')
-                          .includes(related_post: { topic: { posts: :user }})
+                          .includes(related_post: { topic: { ordered_posts: :user }})
                           .where(post_id: post_ids)
 
     post_actions.each do |pa|
@@ -67,13 +67,13 @@ module FlagQuery
       if pa.related_post && pa.related_post.topic
         conversation = {}
         related_topic = pa.related_post.topic
-        if response = related_topic.posts[0]
+        if response = related_topic.ordered_posts[0]
           conversation[:response] = {
             excerpt: excerpt(response.cooked),
             user_id: response.user_id
           }
           user_ids << response.user_id
-          if reply = related_topic.posts[1]
+          if reply = related_topic.ordered_posts[1]
             conversation[:reply] = {
               excerpt: excerpt(reply.cooked),
               user_id: reply.user_id