Fix eager loading polymorphic association with mixed table conditions

This fixes a bug that the `foreign_key` and the `foreign_type` are
separated as different table conditions if a polymorphic association has
a scope that joins another tables.

1 files changed, 13 insertions, 1 deletions

diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
index b37e59038e..126d512068 100644
--- a/activerecord/test/cases/associations/eager_test.rb
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -4,6 +4,7 @@ require "cases/helper"
 require "models/post"
 require "models/tagging"
 require "models/tag"
+require "models/rating"
 require "models/comment"
 require "models/author"
 require "models/essay"
@@ -44,7 +45,7 @@ end
 
 class EagerAssociationTest < ActiveRecord::TestCase
   fixtures :posts, :comments, :authors, :essays, :author_addresses, :categories, :categories_posts,
-            :companies, :accounts, :tags, :taggings, :people, :readers, :categorizations,
+            :companies, :accounts, :tags, :taggings, :ratings, :people, :readers, :categorizations,
             :owners, :pets, :author_favorites, :jobs, :references, :subscribers, :subscriptions, :books,
             :developers, :projects, :developers_projects, :members, :memberships, :clubs, :sponsors
 
@@ -89,6 +90,17 @@ class EagerAssociationTest < ActiveRecord::TestCase
       "expected to find only david's posts"
   end
 
+  def test_loading_polymorphic_association_with_mixed_table_conditions
+    rating = Rating.first
+    assert_equal [taggings(:normal_comment_rating)], rating.taggings_without_tag
+
+    rating = Rating.preload(:taggings_without_tag).first
+    assert_equal [taggings(:normal_comment_rating)], rating.taggings_without_tag
+
+    rating = Rating.eager_load(:taggings_without_tag).first
+    assert_equal [taggings(:normal_comment_rating)], rating.taggings_without_tag
+  end
+
   def test_loading_with_scope_including_joins
     member = Member.first
     assert_equal members(:groucho), member