Fixes issue where calling make_unsaved inside a blueprint forces a ma…

…ke_unsaved instance of the top-level blueprint to be saved.

lib/machinist.rb

@@ -105,11 +105,12 @@ def generate_attribute_value(attribute, *args)
   # that calls to make from within a blueprint don't create
   # anything inside make_unsaved.
   def self.with_save_nerfed
+    prior_nerfed = @@nerfed
     begin
       @@nerfed = true
       yield
     ensure
-      @@nerfed = false
+      @@nerfed = prior_nerfed
     end
   end
 

spec/active_record_spec.rb

@@ -193,6 +193,13 @@ class Comment < ActiveRecord::Base
         post = Post.make_unsaved { comment = Comment.make }
         post.should be_new_record
         comment.should_not be_new_record
+      end
+
+	  it "should not save constructed object when objects are constructed within blueprint" do
+        Comment.blueprint { }
+        Post.blueprint { comment = Comment.make_unsaved }
+        post = Post.make_unsaved
+        post.should be_new_record
       end
     end