Make counter_cache work with polymorphic belongs_to

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3756 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Make counter_cache work with polymorphic belongs_to [Jamis Buck]
+
 * Fixed that calling HasOneProxy#build_model repeatedly would cause saving to happen #4058 [anna@wota.jp]
 
 * Added Sybase database adapter that relies on the Sybase Open Client bindings (see http://raa.ruby-lang.org/project/sybase-ctlib) #3765 [John Sheets]. It's almost completely Active Record compliant, but has the following caveats:

activerecord/lib/active_record/associations.rb

@@ -506,22 +506,22 @@ def belongs_to(association_id, options = {})
             EOF
           end
       
-          if options[:counter_cache]
-            module_eval(
-              "after_create '#{reflection.class_name}.increment_counter(\"#{self.to_s.underscore.pluralize + "_count"}\", #{reflection.primary_key_name})" +
-              " unless #{reflection.name}.nil?'"
-            )
-
-            module_eval(
-              "before_destroy '#{reflection.class_name}.decrement_counter(\"#{self.to_s.underscore.pluralize + "_count"}\", #{reflection.primary_key_name})" +
-              " unless #{reflection.name}.nil?'"
-            )          
-          end
-
           # deprecated api
           deprecated_has_association_method(reflection.name)
           deprecated_association_comparison_method(reflection.name, reflection.class_name)
         end
+
+        if options[:counter_cache]
+          module_eval(
+            "after_create '#{reflection.name}.class.increment_counter(\"#{self.to_s.underscore.pluralize + "_count"}\", #{reflection.primary_key_name})" +
+            " unless #{reflection.name}.nil?'"
+          )
+
+          module_eval(
+            "before_destroy '#{reflection.name}.class.decrement_counter(\"#{self.to_s.underscore.pluralize + "_count"}\", #{reflection.primary_key_name})" +
+            " unless #{reflection.name}.nil?'"
+          )          
+        end
       end
 
       # Associates two classes via an intermediate join table.  Unless the join table is explicitly specified as

activerecord/test/associations_join_model_test.rb

@@ -104,4 +104,12 @@ def test_has_many_going_through_join_model_with_custom_foreign_key
     assert_equal [], posts(:thinking).authors
     assert_equal [authors(:mary)], posts(:authorless).authors
   end
+
+  def test_belongs_to_polymorphic_with_counter_cache
+    assert_equal 0, posts(:welcome)[:taggings_count]
+    tagging = posts(:welcome).taggings.create(:tag => tags(:general))
+    assert_equal 1, posts(:welcome, :reload)[:taggings_count]
+    tagging.destroy
+    assert posts(:welcome, :reload)[:taggings_count].zero?
+  end
 end

activerecord/test/fixtures/db_definitions/schema.rb

@@ -8,6 +8,7 @@
 
   create_table "tags", :force => true do |t|
     t.column "name", :string
+    t.column :taggings_count, :integer, :default => 0
   end
 
   create_table "categorizations", :force => true do |t|
@@ -16,4 +17,6 @@
     t.column "author_id", :integer
   end
 
+  add_column :posts, :taggings_count, :integer, :default => 0
+
 end

activerecord/test/fixtures/tagging.rb

@@ -1,4 +1,4 @@
 class Tagging < ActiveRecord::Base
   belongs_to :tag
-  belongs_to :taggable, :polymorphic => true
+  belongs_to :taggable, :polymorphic => true, :counter_cache => true
 end