Allow counter_cache to accept a column name

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3825 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

 *SVN*
 
+* Allow :counter_cache to take a column name for custom counter cache columns [Jamis Buck]
+
 * Documentation fixes for :dependent [robby@planetargon.com]
 
 * Allow set_fixture_class to take Classes instead of strings for a class in a module.  Raise FixtureClassNotFound if a fixture can't load.  [Rick Olson]

activerecord/lib/active_record/associations.rb

@@ -460,7 +460,8 @@ def has_one(association_id, options = {})
       # * <tt>:counter_cache</tt> - caches the number of belonging objects on the associate class through use of increment_counter 
       #   and decrement_counter. The counter cache is incremented when an object of this class is created and decremented when it's
       #   destroyed. This requires that a column named "#{table_name}_count" (such as comments_count for a belonging Comment class)
-      #   is used on the associate class (such as a Post class).
+      #   is used on the associate class (such as a Post class). You can also specify a custom counter cache column by given that
+      #   name instead of a true/false value to this option (e.g., <tt>:counter_cache => :my_custom_counter</tt>.)
       # * <tt>:include</tt>  - specify second-order associations that should be eager loaded when this object is loaded.
       #
       # Option examples:
@@ -515,13 +516,17 @@ def belongs_to(association_id, options = {})
         end
 
         if options[:counter_cache]
+          cache_column = options[:counter_cache] == true ?
+            "#{self.to_s.underscore.pluralize}_count" :
+            options[:counter_cache]
+
           module_eval(
-            "after_create '#{reflection.name}.class.increment_counter(\"#{self.to_s.underscore.pluralize + "_count"}\", #{reflection.primary_key_name})" +
+            "after_create '#{reflection.name}.class.increment_counter(\"#{cache_column}\", #{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})" +
+            "before_destroy '#{reflection.name}.class.decrement_counter(\"#{cache_column}\", #{reflection.primary_key_name})" +
             " unless #{reflection.name}.nil?'"
           )          
         end

activerecord/test/associations_test.rb

@@ -917,7 +917,27 @@ def test_field_name_same_as_foreign_key
     assert_not_nil computer.developer, ":foreign key == attribute didn't lock up" # '
   end
 
-  def xtest_counter_cache
+  def test_counter_cache
+    topic = Topic.create :title => "Zoom-zoom-zoom"
+    assert_equal 0, topic[:replies_count]
+    
+    reply = Reply.create(:title => "re: zoom", :content => "speedy quick!")
+    reply.topic = topic
+
+    assert_equal 1, topic.reload[:replies_count]
+  end
+
+  def test_custom_counter_cache
+    reply = Reply.create(:title => "re: zoom", :content => "speedy quick!")
+    assert_equal 0, reply[:replies_count]
+
+    silly = SillyReply.create(:title => "gaga", :content => "boo-boo")
+    silly.reply = reply
+
+    assert_equal 1, reply.reload[:replies_count]
+  end
+
+  def xtest_size_uses_counter_cache
     apple = Firm.create("name" => "Apple")
     final_cut = apple.clients.create("name" => "Final Cut")
 

activerecord/test/fixtures/db_definitions/schema.rb

 ActiveRecord::Schema.define do
 
-  create_table "taggings", :force => true do |t|
-    t.column "tag_id", :integer
-    t.column "taggable_type", :string
-    t.column "taggable_id", :integer
+  create_table :taggings, :force => true do |t|
+    t.column :tag_id, :integer
+    t.column :taggable_type, :string
+    t.column :taggable_id, :integer
   end
 
-  create_table "tags", :force => true do |t|
-    t.column "name", :string
+  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|
-    t.column "category_id", :integer
-    t.column "post_id", :integer
-    t.column "author_id", :integer
+  create_table :categorizations, :force => true do |t|
+    t.column :category_id, :integer
+    t.column :post_id, :integer
+    t.column :author_id, :integer
   end
 
   add_column :posts, :taggings_count, :integer, :default => 0

activerecord/test/fixtures/reply.rb

@@ -33,4 +33,5 @@ def validate_on_update
 end
 
 class SillyReply < Reply
+  belongs_to :reply, :foreign_key => "parent_id", :counter_cache => :replies_count
 end