Handle aliased attributes in AR::Relation#select, #order, etc.

With this we can write `Model#select(:aliased)`, `Model#order(:aliased)`,
`Model#reoder(aliased: :desc)`, etc.

Supplementary work to 54122067acaad39b277a5363c6d11d6804c7bf6b.

2 files changed, 35 insertions, 0 deletions

diff --git a/activerecord/test/cases/relation/mutation_test.rb b/activerecord/test/cases/relation/mutation_test.rb
index 7cb2a19bee..4fafa668fb 100644
--- a/activerecord/test/cases/relation/mutation_test.rb
+++ b/activerecord/test/cases/relation/mutation_test.rb
@@ -14,6 +14,10 @@ module ActiveRecord
       def relation_delegate_class(klass)
         self.class.relation_delegate_class(klass)
       end
+
+      def attribute_alias?(name)
+        false
+      end
     end
 
     def relation
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index e874c93110..e390d37871 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -206,12 +206,36 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal topics(:fourth).title, topics.first.title
   end
 
+  def test_finding_with_order_by_aliased_attributes
+    topics = Topic.order(:heading)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_finding_with_assoc_order_by_aliased_attributes
+    topics = Topic.order(heading: :desc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:third).title, topics.first.title
+  end
+
   def test_finding_with_reorder
     topics = Topic.order('author_name').order('title').reorder('id').to_a
     topics_titles = topics.map{ |t| t.title }
     assert_equal ['The First Topic', 'The Second Topic of the day', 'The Third Topic of the day', 'The Fourth Topic of the day', 'The Fifth Topic of the day'], topics_titles
   end
 
+  def test_finding_with_reorder_by_aliased_attributes
+    topics = Topic.order('author_name').reorder(:heading)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:fifth).title, topics.first.title
+  end
+
+  def test_finding_with_assoc_reorder_by_aliased_attributes
+    topics = Topic.order('author_name').reorder(heading: :desc)
+    assert_equal 5, topics.to_a.size
+    assert_equal topics(:third).title, topics.first.title
+  end
+
   def test_finding_with_order_and_take
     entrants = Entrant.order("id ASC").limit(2).to_a
 
@@ -775,6 +799,13 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal david.salary, developer.salary
   end
 
+  def test_select_takes_an_aliased_attribute
+    first = topics(:first)
+
+    topic = Topic.where(id: first.id).select(:heading).first
+    assert_equal first.heading, topic.heading
+  end
+
   def test_select_argument_error
     assert_raises(ArgumentError) { Developer.select }
   end