Support the :primary_key option on a through reflection in a nested through association

activerecord/lib/active_record/associations/through_association_scope.rb

@@ -76,14 +76,11 @@ def construct_through_joins
           right_table_and_alias = table_name_and_alias(right.quoted_table_name, table_aliases[right])
           
           if left.source_reflection.nil?
-            # TODO: Perhaps need to pay attention to left.options[:primary_key] and
-            # left.options[:foreign_key] in places here
-            
             case left.macro
               when :belongs_to
                 joins << inner_join_sql(
                   right_table_and_alias,
-                  table_aliases[left],  left.klass.primary_key,
+                  table_aliases[left],  left.association_primary_key,
                   table_aliases[right], left.primary_key_name,
                   reflection_conditions(right_index)
                 )
@@ -91,7 +88,7 @@ def construct_through_joins
                 joins << inner_join_sql(
                   right_table_and_alias,
                   table_aliases[left],  left.primary_key_name,
-                  table_aliases[right], right.klass.primary_key,
+                  table_aliases[right], right.association_primary_key,
                   polymorphic_conditions(left, left),
                   reflection_conditions(right_index)
                 )

activerecord/test/cases/associations/nested_has_many_through_associations_test.rb

@@ -21,6 +21,7 @@
 require 'models/category'
 require 'models/categorization'
 require 'models/membership'
+require 'models/essay'
 
 # NOTE: Some of these tests might not really test "nested" HMT associations, as opposed to ones which
 # are just one level deep. But it's all the same thing really, as the "nested" code is being 
@@ -31,7 +32,7 @@ class NestedHasManyThroughAssociationsTest < ActiveRecord::TestCase
   fixtures :authors, :books, :posts, :subscriptions, :subscribers, :tags, :taggings,
            :people, :readers, :references, :jobs, :ratings, :comments, :members, :member_details,
            :member_types, :sponsors, :clubs, :organizations, :categories, :categories_posts,
-           :categorizations, :memberships
+           :categorizations, :memberships, :essays
 
   # Through associations can either use the has_many or has_one macros.
   # 
@@ -440,6 +441,20 @@ def test_nested_has_many_through_with_conditions_on_source_associations
     end
   end
   
+  def test_nested_has_many_through_with_foreign_key_option_on_the_source_reflection_through_reflection
+    assert_equal [categories(:general)], organizations(:nsa).author_essay_categories
+    
+    organizations = Organization.joins(:author_essay_categories).
+                                 where('categories.id' => categories(:general).id)
+    assert_equal [organizations(:nsa)], organizations
+    
+    assert_equal categories(:general), organizations(:nsa).author_owned_essay_category
+    
+    organizations = Organization.joins(:author_owned_essay_category).
+                                 where('categories.id' => categories(:general).id)
+    assert_equal [organizations(:nsa)], organizations
+  end
+  
   private
   
     def assert_includes_and_joins_equal(query, expected, association)

activerecord/test/fixtures/authors.yml

@@ -3,6 +3,8 @@ david:
   name: David
   author_address_id: 1
   author_address_extra_id: 2
+  organization_id: No Such Agency
+  owned_essay_id: A Modest Proposal
 
 mary:
   id: 2

activerecord/test/models/author.rb

@@ -110,6 +110,9 @@ def testing_proxy_target
   has_many :essays_2, :primary_key => :name, :class_name => 'Essay', :foreign_key => :author_id
   has_many :essay_categories_2, :through => :essays_2, :source => :category
 
+  belongs_to :owned_essay, :primary_key => :name, :class_name => 'Essay'
+  has_one :owned_essay_category, :through => :owned_essay, :source => :category
+
   belongs_to :author_address,       :dependent => :destroy
   belongs_to :author_address_extra, :dependent => :delete, :class_name => "AuthorAddress"
 

activerecord/test/models/organization.rb

@@ -2,5 +2,11 @@ class Organization < ActiveRecord::Base
   has_many :member_details
   has_many :members, :through => :member_details
 
+  has_many :authors, :primary_key => :name
+  has_many :author_essay_categories, :through => :authors, :source => :essay_categories
+  
+  has_one :author, :primary_key => :name
+  has_one :author_owned_essay_category, :through => :author, :source => :owned_essay_category
+
   scope :clubs, { :from => 'clubs' }
-end
\ No newline at end of file
+end

activerecord/test/schema/schema.rb

@@ -44,6 +44,8 @@ def create_table(*args, &block)
     t.string :name, :null => false
     t.integer :author_address_id
     t.integer :author_address_extra_id
+    t.string :organization_id
+    t.string :owned_essay_id
   end
 
   create_table :author_addresses, :force => true do |t|