don't cache invalid subsets when preloading hmt associations.

closes #8423.

1 files changed, 6 insertions, 0 deletions

diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
index be2d30641e..3bf9125013 100644
--- a/activerecord/test/cases/associations/eager_test.rb
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -1162,4 +1162,10 @@ class EagerAssociationTest < ActiveRecord::TestCase
       Post.where('1 = 0').scoping { Comment.preload(:post).find(1).post }
     )
   end
+
+  test "preloading does not cache has many association subset when preloaded with a through association" do
+    author = Author.includes(:comments_with_order_and_conditions, :posts).first
+    assert_no_queries { assert_equal 2, author.comments_with_order_and_conditions.size }
+    assert_no_queries { assert_equal 5, author.posts.size, "should not cache a subset of the association" }
+  end
 end