Rails1.1で一応動作していると思いきや

Rails1.1

association_join でエラー
ちょっとあせって調べだした。

http://rubyforge.org/forum/forum.php?forum_id=6026

Project: acts_as_encapsulating で
「So we got a lot of work done.

  • association_join changed to wok with altered reflect_on_association
  • reflect_on_association wil now search troug levels of encapsulating to the desired object. Modification of the Association object is made in order to find the correct tabe again later
  • find_with_associations changed to work with allterd Association object
  • find changed. Encapsulated object (one level) is done via include. rest is still with joinstring
  • execute_callstack_for_multiparameter_attributes changed to fix mass asignment...
  • Edited new so it will create an encapsulated object asap

」と書いてあるのでこの辺かな

Module: ActiveRecord::Reflection::ClassMethods
http://api.rubyonrails.org/classes/ActiveRecord/Reflection/ClassMethods.html
に
reflect_on_association が定義されている