fixes #442

app/controllers/forum_posts_controller.rb

@@ -42,7 +42,7 @@ class ForumPostsController < ApplicationController
     @forum_post = ForumPost.find(params[:id])
     check_privilege(@forum_post)
     @forum_post.update_attributes(params[:forum_post])
-    respond_with(@forum_post, :location => forum_post_path(@forum_post))
+    respond_with(@forum_post, :location => forum_topic_path(@forum_post.topic, :page => @forum_post.forum_topic_page))
   end
   
   def destroy

app/models/forum_post.rb

@@ -114,6 +114,10 @@ class ForumPost < ActiveRecord::Base
     "[quote]\n#{creator_name} said:\n\n#{stripped_body}\n[/quote]\n\n"
   end
   
+  def forum_topic_page
+    ((ForumPost.where("topic_id = ? and created_at < ?", topic_id, created_at).count + 1) / Danbooru.config.posts_per_page.to_f).ceil
+  end
+  
   def build_response
     dup.tap do |x|
       x.body = x.quoted_response

app/models/forum_topic.rb

@@ -56,7 +56,7 @@ class ForumTopic < ActiveRecord::Base
   end
   
   def last_page
-    (posts.count / Danbooru.config.posts_per_page.to_f).ceil
+    ((posts.count + 1) / Danbooru.config.posts_per_page.to_f).ceil
   end
   
   def presenter(forum_posts)

test/unit/forum_post_test.rb

@@ -14,6 +14,23 @@ class ForumPostTest < ActiveSupport::TestCase
       CurrentUser.ip_addr = nil
     end
     
+    context "that belongs to a topic with several pages of posts" do
+      setup do
+        Danbooru.config.stubs(:posts_per_page).returns(3)
+        @posts = []
+        10.times do
+          @posts << FactoryGirl.create(:forum_post, :topic_id => @topic.id, :body => rand(100_000))
+        end
+      end
+      
+      should "know which page it's on" do
+        assert_equal(2, @posts[3].forum_topic_page)
+        assert_equal(2, @posts[4].forum_topic_page)
+        assert_equal(2, @posts[5].forum_topic_page)
+        assert_equal(3, @posts[6].forum_topic_page)
+      end
+    end
+    
     context "belonging to a locked topic" do
       setup do
         @post = FactoryGirl.create(:forum_post, :topic_id => @topic.id, :body => "zzz")