From 0fdc2dbe6f14221ccc3244eb749a72c9097e164c Mon Sep 17 00:00:00 2001
From: akihiro17 <coolwizard11@gmail.com>
Date: Thu, 22 Oct 2015 16:11:27 +0900
Subject: [PATCH] Set `scope.reordering_value` to `true` if :reordering values
 are specified

We should call `scope.order!` and set `scope.reordering_value` to `true` if :reordering values are specified

Fixes #21886
---
 activerecord/CHANGELOG.md                      |  6 ++++++
 .../associations/preloader/association.rb      |  4 ++++
 .../test/cases/associations/eager_test.rb      | 18 ++++++++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 86738fa819..614cee4449 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   Set `scope.reordering_value` to `true` if :reordering values are specified.
+
+    Fixes #21886.
+
+    *Hiroaki Izu*
+
 *   Add support for bidirectional destroy dependencies.
 
     Fixes #13609.
diff --git a/activerecord/lib/active_record/associations/preloader/association.rb b/activerecord/lib/active_record/associations/preloader/association.rb
index 29dd0643d6..c43f13f3c4 100644
--- a/activerecord/lib/active_record/associations/preloader/association.rb
+++ b/activerecord/lib/active_record/associations/preloader/association.rb
@@ -136,6 +136,10 @@ def build_scope
           end
           scope.order! preload_values[:order] || values[:order]
 
+          if preload_values[:reordering] || values[:reordering]
+            scope.reordering_value = true
+          end
+
           if preload_values[:readonly] || values[:readonly]
             scope.readonly!
           end
diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
index bc1bff79d3..628ea1c764 100644
--- a/activerecord/test/cases/associations/eager_test.rb
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -1179,6 +1179,24 @@ def test_preloading_has_many_through_with_distinct
     assert_equal 1, mary.unique_categorized_post_ids.length
   end
 
+  def test_preloading_has_one_using_reorder
+    klass = Class.new(ActiveRecord::Base) do
+      def self.name; "TempAuthor"; end
+      self.table_name = "authors"
+      has_one :post, class_name: "PostWithDefaultScope", foreign_key: :author_id
+      has_one :reorderd_post, -> { reorder(title: :desc) }, class_name: "PostWithDefaultScope", foreign_key: :author_id
+    end
+
+    author = klass.first
+    # PRECONDITION: make sure ordering results in different results
+    assert_not_equal author.post, author.reorderd_post
+
+    preloaded_reorderd_post = klass.preload(:reorderd_post).first.reorderd_post
+
+    assert_equal author.reorderd_post, preloaded_reorderd_post
+    assert_equal posts(:sti_post_and_comments).title, preloaded_reorderd_post.title
+  end
+
   def test_preloading_polymorphic_with_custom_foreign_type
     sponsor = sponsors(:moustache_club_sponsor_for_groucho)
     groucho = members(:groucho)