Ensure has_many :through works with changed primary keys [#736 state:resolved]

Signed-off-by: Pratik Naik <pratiknaik@gmail.com>

activerecord/lib/active_record/associations/has_many_through_association.rb

@@ -150,7 +150,7 @@ module ActiveRecord
             end
           else
             reflection_primary_key = @reflection.source_reflection.primary_key_name
-            source_primary_key     = @reflection.klass.primary_key
+            source_primary_key     = @reflection.through_reflection.klass.primary_key
             if @reflection.source_reflection.options[:as]
               polymorphic_join = "AND %s.%s = %s" % [
                 @reflection.quoted_table_name, "#{@reflection.source_reflection.options[:as]}_type",

activerecord/test/cases/associations/has_many_through_associations_test.rb

@@ -8,9 +8,12 @@ require 'models/comment'
 require 'models/tag'
 require 'models/tagging'
 require 'models/author'
+require 'models/owner'
+require 'models/pet'
+require 'models/toy'
 
 class HasManyThroughAssociationsTest < ActiveRecord::TestCase
-  fixtures :posts, :readers, :people, :comments, :authors
+  fixtures :posts, :readers, :people, :comments, :authors, :owners, :pets, :toys
 
   def test_associate_existing
     assert_queries(2) { posts(:thinking);people(:david) }
@@ -251,4 +254,8 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     author.author_favorites.create(:favorite_author_id => 3)
     assert_equal post.author.author_favorites, post.author_favorites
   end
+
+  def test_has_many_association_through_a_has_many_association_with_nonstandard_primary_keys
+    assert_equal 1, owners(:blackbeard).toys.count
+  end
 end

activerecord/test/fixtures/toys.yml

@@ -0,0 +1,4 @@
+bone:
+  toy_id: 1
+  name: Bone
+  pet_id: 1

activerecord/test/models/owner.rb

@@ -1,4 +1,5 @@
 class Owner < ActiveRecord::Base
   set_primary_key :owner_id
   has_many :pets
-end
+  has_many :toys, :through => :pets
+end

activerecord/test/models/pet.rb

@@ -1,4 +1,5 @@
 class Pet < ActiveRecord::Base
   set_primary_key :pet_id
   belongs_to :owner
-end
+  has_many :toys
+end

activerecord/test/models/toy.rb

@@ -0,0 +1,4 @@
+class Toy < ActiveRecord::Base
+  set_primary_key :toy_id
+  belongs_to :pet
+end

activerecord/test/schema/schema.rb

@@ -425,6 +425,11 @@ ActiveRecord::Schema.define do
     t.column :taggings_count, :integer, :default => 0
   end
 
+  create_table :toys, :primary_key => :toy_id ,:force => true do |t|
+    t.string :name
+    t.integer :pet_id, :integer
+  end
+
   create_table :treasures, :force => true do |t|
     t.column :name, :string
     t.column :looter_id, :integer