Adding test_has_many_through_has_one_with_has_many_through_source_ref…

…lection and modifying ThroughAssociationScope to make it work correctly.

activerecord/lib/active_record/associations/through_association_scope.rb

@@ -73,7 +73,7 @@ def construct_through_joins
               case left.macro
                 when :belongs_to
                   left_primary_key  = left.klass.primary_key
-                  right_primary_key = right.primary_key_name
+                  right_primary_key = left.primary_key_name
                 when :has_many, :has_one
                   left_primary_key  = left.primary_key_name
                   right_primary_key = right.klass.primary_key

activerecord/test/cases/associations/nested_has_many_through_associations_test.rb

@@ -23,6 +23,7 @@
 require 'models/member_type'
 require 'models/sponsor'
 require 'models/club'
+require 'models/organization'
 
 # 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 
@@ -32,7 +33,7 @@
 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
+           :member_types, :sponsors, :clubs, :organizations
 
   # Through associations can either use the has_many or has_one macros.
   # 
@@ -113,9 +114,25 @@ def test_has_many_through_has_one_through_with_has_one_source_reflection
     # assert_equal [sponsors(:moustache_club_sponsor_for_groucho)], members.first.nested_sponsors
   end
 
-  # TODO: has_many through
+  # has_many through
   # Source: has_many through
   # Through: has_one
+  def test_has_many_through_has_one_with_has_many_through_source_reflection
+    assert_equal [member_details(:groucho), member_details(:some_other_guy)],
+                 members(:groucho).organization_member_details
+
+    members = Member.joins(:organization_member_details).
+                     where('member_details.id' => member_details(:groucho).id)
+    assert_equal [members(:groucho), members(:some_other_guy)], members
+
+    members = Member.joins(:organization_member_details).
+                     where('member_details.id' => 9)
+    assert members.empty?
+
+    members = Member.includes(:organization_member_details)
+    assert_equal [member_details(:groucho), member_details(:some_other_guy)],
+                 members.first.organization_member_details
+  end
 
   # TODO: has_many through
   # Source: has_many

activerecord/test/fixtures/member_details.yml

@@ -1,3 +1,8 @@
 groucho:
   id: 1
   member_id: 1
+  organization: nsa
+some_other_guy:
+  id: 2
+  member_id: 2
+  organization: nsa

activerecord/test/models/member.rb

@@ -15,4 +15,6 @@ class Member < ActiveRecord::Base
 
   has_many :nested_sponsors, :through => :sponsor_club, :source => :sponsor
   has_one :nested_sponsor, :through => :sponsor_club, :source => :sponsor
+
+  has_many :organization_member_details, :through => :member_detail
 end

activerecord/test/models/member_detail.rb

@@ -2,4 +2,6 @@ class MemberDetail < ActiveRecord::Base
   belongs_to :member
   belongs_to :organization
   has_one :member_type, :through => :member
+
+  has_many :organization_member_details, :through => :organization, :source => :member_details
 end