6 files changed, 18 insertions, 4 deletions
diff --git a/activerecord/lib/active_record/associations/belongs_to_association.rb b/activerecord/lib/active_record/associations/belongs_to_association.rb
index 1752678cbd..f5557618c4 100644
--- a/activerecord/lib/active_record/associations/belongs_to_association.rb
+++ b/activerecord/lib/active_record/associations/belongs_to_association.rb
@@ -13,7 +13,7 @@ module ActiveRecord
         counter_cache_name = @reflection.counter_cache_column
 
         if record.nil?
-          if counter_cache_name && @owner[counter_cache_name] && !@owner.new_record?
+          if counter_cache_name && !@owner.new_record?
             @reflection.klass.decrement_counter(counter_cache_name, @owner[@reflection.primary_key_name]) if @owner[@reflection.primary_key_name]
           end
 
diff --git a/activerecord/test/cases/associations_test.rb b/activerecord/test/cases/associations_test.rb
index a15abf90a6..0df508d01d 100755
--- a/activerecord/test/cases/associations_test.rb
+++ b/activerecord/test/cases/associations_test.rb
@@ -1308,6 +1308,18 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_equal 0, Topic.find(debate.id).send(:read_attribute, "replies_count"), "First reply deleted"
   end
 
+  def test_belongs_to_counter_with_assigning_nil
+    p = Post.find(1)
+    c = Comment.find(1)
+
+    assert_equal p.id, c.post_id
+    assert_equal 2, Post.find(p.id).comments.size
+
+    c.post = nil
+
+    assert_equal 1, Post.find(p.id).comments.size
+  end
+
   def test_belongs_to_counter_with_reassigning
     t1 = Topic.create("title" => "t1")
     t2 = Topic.create("title" => "t2")
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index 4339b725c8..04ed751eb5 100755
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -877,7 +877,7 @@ class BasicsTest < ActiveRecord::TestCase
   end
 
   def test_readonly_attributes
-    assert_equal Set.new([ 'title' ]), ReadonlyTitlePost.readonly_attributes
+    assert_equal Set.new([ 'title', 'comments_count' ]), ReadonlyTitlePost.readonly_attributes
 
     post = ReadonlyTitlePost.create(:title => "cannot change this", :body => "changeable")
     post.reload
diff --git a/activerecord/test/fixtures/posts.yml b/activerecord/test/fixtures/posts.yml
index 0f1445b638..92e5d1908f 100644
--- a/activerecord/test/fixtures/posts.yml
+++ b/activerecord/test/fixtures/posts.yml
@@ -3,6 +3,7 @@ welcome:
   author_id: 1
   title: Welcome to the weblog
   body: Such a lovely day
+  comments_count: 2
   type: Post
 
 thinking:
diff --git a/activerecord/test/models/comment.rb b/activerecord/test/models/comment.rb
index 60ca082c2e..73ebdadf73 100644
--- a/activerecord/test/models/comment.rb
+++ b/activerecord/test/models/comment.rb
@@ -1,5 +1,5 @@
 class Comment < ActiveRecord::Base
-  belongs_to :post
+  belongs_to :post, :counter_cache => true
 
   def self.what_are_you
     'a comment...'
@@ -20,4 +20,4 @@ class VerySpecialComment < Comment
   def self.what_are_you
     'a very special comment...'
   end
-end
-\ No newline at end of file
+end
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index 307ad8b935..44bbb48773 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -154,6 +154,7 @@ ActiveRecord::Schema.define do
       t.string  :title, :null => false
       t.text    :body, :null => false
       t.string  :type
+      t.integer :comments_count, :default => 0
     end
 
     create_table :projects, :force => true do |t|