backport #8403, no intermediate AR objects when eager loading.

Closes #3313

Conflicts:

	activerecord/CHANGELOG.md
	activerecord/test/models/developer.rb

2 files changed, 15 insertions, 0 deletions

diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
index bf01b46852..d3601e0dba 100644
--- a/activerecord/test/cases/associations/eager_test.rb
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -916,6 +916,12 @@ class EagerAssociationTest < ActiveRecord::TestCase
     assert_equal 3, Developer.find(:all, :include => 'projects', :conditions => 'developers_projects.access_level = 1', :limit => 5).size
   end
 
+  def test_dont_create_temporary_active_record_instances
+    Developer.instance_count = 0
+    developers = Developer.find(:all, :include => 'projects', :conditions => 'developers_projects.access_level = 1', :limit => 5).to_a
+    assert_equal developers.count, Developer.instance_count
+  end
+
   def test_order_on_join_table_with_include_and_limit
     assert_equal 5, Developer.find(:all, :include => 'projects', :order => 'developers_projects.joined_on DESC', :limit => 5).size
   end
diff --git a/activerecord/test/models/developer.rb b/activerecord/test/models/developer.rb
index 4dc9fff9fd..a730d86586 100644
--- a/activerecord/test/models/developer.rb
+++ b/activerecord/test/models/developer.rb
@@ -63,6 +63,15 @@ class Developer < ActiveRecord::Base
       self.all
     end
   end
+
+  after_find :track_instance_count
+  cattr_accessor :instance_count
+
+  def track_instance_count
+    self.class.instance_count ||= 0
+    self.class.instance_count += 1
+  end
+  private :track_instance_count
 end
 
 class AuditLog < ActiveRecord::Base