Merge pull request #9391 from senny/8663_broken_hmt_ordering_with_includes

don't apply invalid ordering when preloading hmt associations.

activerecord/CHANGELOG.md

@@ -1,5 +1,11 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Preloading ordered `has_many :through` associations does no longer
+    apply invalid ordering to the `:through` association.
+    Fixes #8663.
+
+    *Yves Senn*
+
 *   The auto explain feature has been removed. This feature was
     activated by configuring `config.active_record.auto_explain_threshold_in_seconds`.
     The configuration option was deprecated and has no more effect.

activerecord/lib/active_record/associations/preloader/through_association.rb

@@ -47,12 +47,12 @@ module ActiveRecord
             through_scope.where! reflection.foreign_type => options[:source_type]
           else
             unless reflection_scope.where_values.empty?
-              through_scope.includes_values = reflection_scope.values[:includes] || options[:source]
+              through_scope.includes_values = Array(reflection_scope.values[:includes] || options[:source])
               through_scope.where_values    = reflection_scope.values[:where]
             end
 
-            through_scope.order!      reflection_scope.values[:order]
             through_scope.references! reflection_scope.values[:references]
+            through_scope.order! reflection_scope.values[:order] if through_scope.eager_loading?
           end
 
           through_scope

activerecord/test/cases/associations/eager_test.rb

@@ -73,6 +73,11 @@ class EagerAssociationTest < ActiveRecord::TestCase
     end
   end
 
+  def test_has_many_through_with_order
+    authors = Author.includes(:favorite_authors).to_a
+    assert_no_queries { authors.map(&:favorite_authors) }
+  end
+
   def test_with_two_tables_in_from_without_getting_double_quoted
     posts = Post.select("posts.*").from("authors, posts").eager_load(:comments).where("posts.author_id = authors.id").order("posts.id").to_a
     assert_equal 2, posts.first.comments.size