Allow polymorphic has_one to work when the association is set before the owner has been saved. Fixes #1524.

2 files changed, 12 insertions, 3 deletions

diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index 0ccf74c7a4..c3aee90124 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -177,9 +177,7 @@ module ActiveRecord
 
         # Sets the owner attributes on the given record
         def set_owner_attributes(record)
-          if owner.persisted?
-            creation_attributes.each { |key, value| record[key] = value }
-          end
+          creation_attributes.each { |key, value| record[key] = value }
         end
 
         # Should be true if there is a foreign key present on the owner which
diff --git a/activerecord/test/cases/associations/join_model_test.rb b/activerecord/test/cases/associations/join_model_test.rb
index 785ea079ed..f22a91be2d 100644
--- a/activerecord/test/cases/associations/join_model_test.rb
+++ b/activerecord/test/cases/associations/join_model_test.rb
@@ -145,6 +145,17 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase
     assert_equal posts(:thinking),    tagging.taggable
   end
 
+  def test_set_polymorphic_has_one_on_new_record
+    tagging = tags(:misc).taggings.create
+    post = Post.new :title => "foo", :body => "bar"
+    post.tagging = tagging
+    post.save!
+
+    assert_equal "Post",  tagging.taggable_type
+    assert_equal post.id, tagging.taggable_id
+    assert_equal post,    tagging.taggable
+  end
+
   def test_create_polymorphic_has_many_with_scope
     old_count = posts(:welcome).taggings.count
     tagging = posts(:welcome).taggings.create(:tag => tags(:misc))