Infinite loop when using has_many :through with nonstandard keys

If you attempt the create a has_many :through association that uses a has_many association with nonstandard primary and foreign keys, you will get an infinite loop when trying to use the association.

This happens because the association calls owner_quoted_id in construct_quoted_owner_attributes, and owner_quoted_id calls quote_value. The problem is that quote_value is not defined on the association itself and needs to be called through method_missing. The method_missing implementation in association_collection tries to send the method through to the reflection's class, but only after calling construct_scope, and that method ends up calling owner_quoted_id again, creating an infinite loop. The attached patch against 2-3-stable implements the quote_value method on AssociationCollection to send the call directly to the reflection's class without going through method_missing.

Here is a code example:

class MailingList < ActiveRecord::Base
  has_many :subscriptions
end

class Subscription < ActiveRecord::Base
  belongs_to :mailing_list
  belongs_to :user, :primary_key => :email, :foreign_key => :email
end

class User < ActiveRecord::Base
  has_many :subscriptions, :primary_key => :email, :foreign_key => :email, :dependent => :destroy
  has_many :mailing_lists, :through => :subscriptions, :primary_key => :email, :foreign_key => :email
end

User.first.mailing_lists => # infinite loop