Fix multiple self-referencing eager loads failing to join multiple times

[#4679 state:committed]

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

activerecord/lib/active_record/associations.rb

@@ -1903,7 +1903,7 @@ def initialize(active_record, joins = nil)
             end
 
             def ==(other)
-              other.is_a?(JoinBase) &&
+              other.class == self.class &&
               other.active_record == active_record &&
               other.table_joins == table_joins
             end
@@ -1974,7 +1974,7 @@ def initialize(reflection, join_dependency, parent = nil)
             end
 
             def ==(other)
-              other.is_a?(JoinAssociation) &&
+              other.class == self.class &&
               other.reflection == reflection &&
               other.parent == parent
             end

activerecord/test/cases/associations/cascaded_eager_loading_test.rb

@@ -7,9 +7,10 @@
 require 'models/company'
 require 'models/topic'
 require 'models/reply'
+require 'models/person'
 
 class CascadedEagerLoadingTest < ActiveRecord::TestCase
-  fixtures :authors, :mixins, :companies, :posts, :topics, :accounts, :comments, :categorizations
+  fixtures :authors, :mixins, :companies, :posts, :topics, :accounts, :comments, :categorizations, :people
 
   def test_eager_association_loading_with_cascaded_two_levels
     authors = Author.find(:all, :include=>{:posts=>:comments}, :order=>"authors.id")
@@ -38,6 +39,13 @@ def test_eager_association_loading_with_hmt_does_not_table_name_collide_when_joi
     assert_equal 9, assert_no_queries { authors[0].comments.size }
   end
 
+  def test_eager_association_loading_grafts_stashed_associations_to_correct_parent
+    assert_nothing_raised do
+      Person.eager_load(:primary_contact => :primary_contact).where('primary_contacts_people_2.first_name = ?', 'Susan').all
+    end
+    assert_equal people(:michael), Person.eager_load(:primary_contact => :primary_contact).where('primary_contacts_people_2.first_name = ?', 'Susan').first
+  end
+
   def test_eager_association_loading_with_cascaded_two_levels_with_two_has_many_associations
     authors = Author.find(:all, :include=>{:posts=>[:comments, :categorizations]}, :order=>"authors.id")
     assert_equal 2, authors.size