Add failing test case for preloading polymorphic association across multiple databases with same table name

Author: summera

activerecord/test/cases/associations_test.rb

@@ -39,6 +39,8 @@
 require "models/cpk"
 require "models/member_detail"
 require "models/organization"
+require "models/dog"
+require "models/other_dog"
 
 
 class AssociationsTest < ActiveRecord::TestCase
@@ -773,7 +775,8 @@ def test_associations_raise_with_name_error_if_associated_to_classes_that_do_not
 class PreloaderTest < ActiveRecord::TestCase
   fixtures :posts, :comments, :books, :authors, :tags, :taggings, :essays, :categories, :author_addresses,
            :sharded_blog_posts, :sharded_comments, :sharded_blog_posts_tags, :sharded_tags,
-           :members, :member_details, :organizations, :cpk_orders, :cpk_order_agreements
+           :members, :member_details, :organizations, :cpk_orders, :cpk_order_agreements,
+           :dogs, :other_dogs
 
   def test_preload_with_scope
     post = posts(:welcome)
@@ -1206,6 +1209,23 @@ def test_preload_does_not_group_same_scope_different_key_name
     end
   end
 
+  def test_multi_database_polymorphic_preload_with_same_table_name
+    dog = dogs(:sophie)
+    dog_comment = comments(:greetings)
+    dog_comment.origin_type = dog.class.name
+    dog_comment.origin_id = dog.id
+
+    other_dog = other_dogs(:lassie)
+    other_dog_comment = comments(:more_greetings)
+    other_dog_comment.origin_type = other_dog.class.name
+    other_dog_comment.origin_id = other_dog.id
+
+    assert_queries(2) do
+      preloader = ActiveRecord::Associations::Preloader.new(records: [dog_comment, other_dog_comment], associations: :origin)
+      preloader.call
+    end
+  end
+
   def test_preload_with_available_records
     post = posts(:welcome)
     david = authors(:david)