Provide Association Extensions access to the instance that the association is being accessed from. Closes #4433 [josh@hasmanythrough.com]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4372 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,8 @@
 *SVN*
 
+* Provide Association Extensions access to the instance that the association is being accessed from.  
+  Closes #4433 [josh@hasmanythrough.com]
+
 * Update OpenBase adaterp's maintainer's email address. Closes #5176. [Derrick Spell]
 
 * Add a quick note about :select and eagerly included associations. [Rick]

activerecord/lib/active_record/associations.rb

@@ -232,6 +232,13 @@ module ActiveRecord
     #     has_many :people, :extend => [FindOrCreateByNameExtension, FindRecentExtension]
     #   end
     #
+    # Some extensions can only be made to work with knowledge of the association proxy's internals.
+    # Extensions can access relevant state using accessors on the association proxy:
+    # 
+    # * +proxy_owner+ - Returns the object the association is part of.
+    # * +proxy_reflection+ - Returns the reflection object that describes the association.
+    # * +proxy_target+ - Returns the associated object for belongs_to and has_one, or the collection of associated objects for has_many and has_and_belongs_to_many.
+    #
     # === Association Join Models
     # 
     # Has Many associations can be configured with the :through option to use an explicit join model to retrieve the data.  This

activerecord/lib/active_record/associations/association_proxy.rb

@@ -4,7 +4,7 @@ module ActiveRecord
       attr_reader :reflection
       alias_method :proxy_respond_to?, :respond_to?
       alias_method :proxy_extend, :extend
-      instance_methods.each { |m| undef_method m unless m =~ /(^__|^nil\?|^proxy_respond_to\?|^proxy_extend|^send)/ }
+      instance_methods.each { |m| undef_method m unless m =~ /(^__|^nil\?$|^send$|proxy_)/ }
 
       def initialize(owner, reflection)
         @owner, @reflection = owner, reflection
@@ -12,6 +12,18 @@ module ActiveRecord
         reset
       end
       
+      def proxy_owner
+        @owner
+      end
+      
+      def proxy_reflection
+        @reflection
+      end
+      
+      def proxy_target
+        @target
+      end
+      
       def respond_to?(symbol, include_priv = false)
         proxy_respond_to?(symbol, include_priv) || (load_target && @target.respond_to?(symbol, include_priv))
       end

activerecord/test/associations_test.rb

@@ -65,6 +65,29 @@ class AssociationsTest < Test::Unit::TestCase
   end
 end
 
+class AssociationProxyTest < Test::Unit::TestCase
+  fixtures :authors, :posts
+  
+  def test_proxy_accessors
+    welcome = posts(:welcome)
+    assert_equal  welcome, welcome.author.proxy_owner
+    assert_equal  welcome.class.reflect_on_association(:author), welcome.author.proxy_reflection
+    welcome.author.class  # force load target
+    assert_equal  welcome.author, welcome.author.proxy_target
+
+    david = authors(:david)
+    assert_equal  david, david.posts.proxy_owner
+    assert_equal  david.class.reflect_on_association(:posts), david.posts.proxy_reflection
+    david.posts.first   # force load target
+    assert_equal  david.posts, david.posts.proxy_target
+    
+    assert_equal  david, david.posts_with_extension.testing_proxy_owner
+    assert_equal  david.class.reflect_on_association(:posts_with_extension), david.posts_with_extension.testing_proxy_reflection
+    david.posts_with_extension.first   # force load target
+    assert_equal  david.posts_with_extension, david.posts_with_extension.testing_proxy_target
+  end
+end
+
 class HasOneAssociationsTest < Test::Unit::TestCase
   fixtures :accounts, :companies, :developers, :projects, :developers_projects
   

activerecord/test/fixtures/author.rb

@@ -3,6 +3,17 @@ class Author < ActiveRecord::Base
   has_many :posts_with_comments, :include => :comments, :class_name => "Post"
   has_many :posts_with_categories, :include => :categories, :class_name => "Post"
   has_many :posts_with_comments_and_categories, :include => [ :comments, :categories ], :order => "posts.id", :class_name => "Post"
+  has_many :posts_with_extension, :class_name => "Post" do #, :extend => ProxyTestExtension
+    def testing_proxy_owner
+      proxy_owner
+    end
+    def testing_proxy_reflection
+      proxy_reflection
+    end
+    def testing_proxy_target
+      proxy_target
+    end
+  end
   has_many :comments, :through => :posts
   has_many :funky_comments, :through => :posts, :source => :comments