reintroduce patch from #726 to handle nested eager loading via associ…

…ations

activerecord/lib/active_record/associations/join_dependency.rb

@@ -184,7 +184,7 @@ def construct_association(record, join_part, row)
 
         macro = join_part.reflection.macro
         if macro == :has_one
-          return if record.association_cache.key?(join_part.reflection.name)
+          return record.association(join_part.reflection.name).target if record.association_cache.key?(join_part.reflection.name)
           association = join_part.instantiate(row) unless row[join_part.aliased_primary_key].nil?
           set_target_and_inverse(join_part, association, record)
         else

activerecord/test/cases/associations/eager_test.rb

@@ -252,6 +252,41 @@ def test_nested_loading_with_no_associations
     end
   end
 
+  def test_nested_loading_through_has_one_association
+    aa = AuthorAddress.find(author_addresses(:david_address).id, :include => {:author => :posts})
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_order
+    aa = AuthorAddress.find(author_addresses(:david_address).id, :include => {:author => :posts}, :order => 'author_addresses.id')
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_order_on_association
+    aa = AuthorAddress.find(author_addresses(:david_address).id, :include => {:author => :posts}, :order => 'authors.id')
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_order_on_nested_association
+    aa = AuthorAddress.find(author_addresses(:david_address).id, :include => {:author => :posts}, :order => 'posts.id')
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_conditions
+    aa = AuthorAddress.find(author_addresses(:david_address).id, :include => {:author => :posts}, :conditions => "author_addresses.id > 0")
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_conditions_on_association
+    aa = AuthorAddress.find(author_addresses(:david_address).id, :include => {:author => :posts}, :conditions => "authors.id > 0")
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
+  def test_nested_loading_through_has_one_association_with_conditions_on_nested_association
+    aa = AuthorAddress.find(author_addresses(:david_address).id, :include => {:author => :posts}, :conditions => "posts.id > 0")
+    assert_equal aa.author.posts.count, aa.author.posts.length
+  end
+
   def test_eager_association_loading_with_belongs_to_and_foreign_keys
     pets = Pet.find(:all, :include => :owner)
     assert_equal 3, pets.length