Ensure hm:t#create/create! throws ActiveRecord::RecordNotSaved when the owner is new

activerecord/lib/active_record/associations/has_many_through_association.rb

@@ -8,6 +8,8 @@ module ActiveRecord
       alias_method :new, :build
 
       def create!(attrs = nil)
+        ensure_owner_is_not_new
+
         transaction do
           self << (object = attrs ? @reflection.klass.send(:with_scope, :create => attrs) { @reflection.create_association! } : @reflection.create_association!)
           object
@@ -15,6 +17,8 @@ module ActiveRecord
       end
 
       def create(attrs = nil)
+        ensure_owner_is_not_new
+
         transaction do
           self << (object = attrs ? @reflection.klass.send(:with_scope, :create => attrs) { @reflection.create_association } : @reflection.create_association)
           object

activerecord/test/cases/associations/has_many_through_associations_test.rb

@@ -169,6 +169,13 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     assert_equal peeps + 1, posts(:thinking).people.count
   end
 
+  def test_create_on_new_record
+    p = Post.new
+
+    assert_raises(ActiveRecord::RecordNotSaved) { p.people.create(:first_name => "mew") }
+    assert_raises(ActiveRecord::RecordNotSaved) { p.people.create!(:first_name => "snow") }
+  end
+
   def test_clear_associations
     assert_queries(2) { posts(:welcome);posts(:welcome).people(true) }