5 files changed, 31 insertions, 4 deletions
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 80b3e23026..65a1319c7e 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -1003,9 +1003,7 @@ module ActiveRecord
 
         # Create the callbacks to update counter cache
         if options[:counter_cache]
-          cache_column = options[:counter_cache] == true ?
-            "#{self.to_s.demodulize.underscore.pluralize}_count" :
-            options[:counter_cache]
+          cache_column = reflection.counter_cache_column
 
           method_name = "belongs_to_counter_cache_after_create_for_#{reflection.name}".to_sym
           define_method(method_name) do
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index e69bfb1355..2d4c1d5507 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -197,7 +197,7 @@ module ActiveRecord
 
       def counter_cache_column
         if options[:counter_cache] == true
-          "#{active_record.name.underscore.pluralize}_count"
+          "#{active_record.name.demodulize.underscore.pluralize}_count"
         elsif options[:counter_cache]
           options[:counter_cache]
         end
diff --git a/activerecord/test/cases/associations/belongs_to_associations_test.rb b/activerecord/test/cases/associations/belongs_to_associations_test.rb
index 92ed465ae7..78b90121b4 100644
--- a/activerecord/test/cases/associations/belongs_to_associations_test.rb
+++ b/activerecord/test/cases/associations/belongs_to_associations_test.rb
@@ -154,6 +154,23 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_equal 0, Topic.find(t2.id).replies.size
   end
 
+  def test_belongs_to_reassign_with_namespaced_models_and_counters
+    t1 = Web::Topic.create("title" => "t1")
+    t2 = Web::Topic.create("title" => "t2")
+    r1 = Web::Reply.new("title" => "r1", "content" => "r1")
+    r1.topic = t1
+
+    assert r1.save
+    assert_equal 1, Web::Topic.find(t1.id).replies.size
+    assert_equal 0, Web::Topic.find(t2.id).replies.size
+
+    r1.topic = Web::Topic.find(t2.id)
+
+    assert r1.save
+    assert_equal 0, Web::Topic.find(t1.id).replies.size
+    assert_equal 1, Web::Topic.find(t2.id).replies.size
+  end
+
   def test_belongs_to_counter_after_save
     topic = Topic.create!(:title => "monday night")
     topic.replies.create!(:title => "re: monday night", :content => "football")
diff --git a/activerecord/test/models/reply.rb b/activerecord/test/models/reply.rb
index 812bc1f535..1c990acab6 100644
--- a/activerecord/test/models/reply.rb
+++ b/activerecord/test/models/reply.rb
@@ -37,3 +37,9 @@ end
 class SillyReply < Reply
   belongs_to :reply, :foreign_key => "parent_id", :counter_cache => :replies_count
 end
+
+module Web
+  class Reply < Web::Topic
+    belongs_to :topic, :foreign_key => "parent_id", :counter_cache => true, :class_name => 'Web::Topic'
+  end
+end
+\ No newline at end of file
diff --git a/activerecord/test/models/topic.rb b/activerecord/test/models/topic.rb
index 2fe846db48..f1b7bbae3b 100644
--- a/activerecord/test/models/topic.rb
+++ b/activerecord/test/models/topic.rb
@@ -71,3 +71,9 @@ class Topic < ActiveRecord::Base
       end
     end
 end
+
+module Web
+  class Topic < ActiveRecord::Base
+    has_many :replies, :dependent => :destroy, :foreign_key => "parent_id", :class_name => 'Web::Reply'
+  end
+end
+\ No newline at end of file