Define collection singular ids method for has_many :through associations. Closes #8763.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7137 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

 *SVN*
 
+* Define collection singular ids method for has_many :through associations.  #8763 [lifofifo]
+
 * Array attribute conditions work with proxied association collections.  #8318 [kamal, theamazingrando]
 
 * Fix polymorphic has_one associations declared in an abstract class.  #8638 [lifofifo, daxhuiberts]

activerecord/lib/active_record/associations.rb

@@ -674,6 +674,7 @@ def has_many(association_id, options = {}, &extension)
 
         if options[:through]
           collection_reader_method(reflection, HasManyThroughAssociation)
+          collection_accessor_methods(reflection, HasManyThroughAssociation, false)
         else
           add_multiple_associated_save_callbacks(reflection.name)
           add_association_callbacks(reflection.name, reflection.options)
@@ -1060,7 +1061,7 @@ def collection_reader_method(reflection, association_proxy_class)
           end
         end
 
-        def collection_accessor_methods(reflection, association_proxy_class)
+        def collection_accessor_methods(reflection, association_proxy_class, writer = true)
           collection_reader_method(reflection, association_proxy_class)
 
           define_method("#{reflection.name}=") do |new_value|
@@ -1077,7 +1078,7 @@ def collection_accessor_methods(reflection, association_proxy_class)
           define_method("#{reflection.name.to_s.singularize}_ids=") do |new_value|
             ids = (new_value || []).reject { |nid| nid.blank? }
             send("#{reflection.name}=", reflection.class_name.constantize.find(ids))
-          end
+          end if writer
         end
 
         def add_multiple_associated_save_callbacks(association_name)

activerecord/test/associations_test.rb

@@ -11,6 +11,7 @@
 require 'fixtures/category'
 require 'fixtures/post'
 require 'fixtures/author'
+require 'fixtures/comment'
 require 'fixtures/tag'
 require 'fixtures/tagging'
 
@@ -420,7 +421,7 @@ def test_deprecated_inferred_foreign_key
 
 class HasManyAssociationsTest < Test::Unit::TestCase
   fixtures :accounts, :companies, :developers, :projects,
-           :developers_projects, :topics
+           :developers_projects, :topics, :authors, :comments
 
   def setup
     Client.destroyed_client_ids.clear
@@ -1014,14 +1015,21 @@ def test_assign_ids
   end
 
   def test_assign_ids_ignoring_blanks
-    firm = Firm.new("name" => "Apple")
+    firm = Firm.create!(:name => 'Apple')
     firm.client_ids = [companies(:first_client).id, nil, companies(:second_client).id, '']
-    firm.save
-    firm.reload
-    assert_equal 2, firm.clients.length
+    firm.save!
+
+    assert_equal 2, firm.clients(true).size
     assert firm.clients.include?(companies(:second_client))
   end
 
+  def test_get_ids_for_through
+    assert_equal [comments(:eager_other_comment1).id], authors(:mary).comment_ids
+  end
+
+  def test_assign_ids_for_through
+    assert_raise(NoMethodError) { authors(:mary).comment_ids = [123] }
+  end
 end
 
 class BelongsToAssociationsTest < Test::Unit::TestCase