class_cache has got me stumped

I was working on a project this weekend and came across an issue that hung me up for hours. The application will have an area to manage contacts, so I have a Person model, which has_many email_addresses, among other things. So in order to add another email_address to my form using rjs, I send a request to the ContactMethodsController with a the type param set to email_address. It renders the rjs, which renders a partial and inserts it into my form. In order to accomplish this I needed to generate a temporary ID for each email address so I could use them in a form, generate urls with them, and when/if errors occur the id would remain the same so the form could pick up the errors. I do not want to save the models unless they are filled in. This scheme works wonderfully in development, but when I push it to production, it breaks because the generated id becomes nil after an action other than index/new is run in the PeopleController. The index action can be refreshed, but as soon as another action is called it blows up.

class Person < ActiveRecord::Base

  with_options :dependent => :destroy do |person|     person.has_many :phone_numbers, :as => :phoneable     person.has_many :email_addresses, :as => :emailable     person.has_many :addresses, :as => :addressable   end

  def update_contact_methods(data)   result = {}   [ :email_addresses, :phone_numbers, :addresses ].collect do |c|     klass = c.to_s.classify.constantize     x = c.to_s.singularize.split('_')[0]

    klass.transaction do     unless new_record?       klass.destroy_all("#{x}able_id = #{self.id} AND #{x}able_type = '#{self.class}'")     end       result[c] = data[c].values.collect{|v| klass.new(v) }.delete_if(&:blank?)     end   end   update_attributes(result)   end

  def update_from_params(person_params)   contact_params = person_params.delete(:contact_data)

  update_attributes(person_params)   reload

  update_contact_methods(contact_params)

  errors.empty?   end

  def set_place_holder_data   # give the person a temp id   self.id ||= 0

  # add an address it there is none   self.addresses = [ self.addresses.build ] if self.addresses.empty?

  # add phone numbers if we have none   self.email_addresses = [ self.email_addresses.build ] if self.email_addresses.empty?

  # add phone numbers if we have none   self.phone_numbers = [ self.phone_numbers.build ] if self.phone_numbers.empty?   end

end

Note that when set_place_holder_data is called a temporary id of 0 is set if the id is not set and we add a dummy email_address if one does not exist, so the fields show up on the form.

[code=]class EmailAddress < ActiveRecord::Base

  ##### Associations

  belongs_to :emailable, :polymorphic => true

  ##### Attributes

  cattr_reader :locations   @@locations = %w(HOME WORK OTHER)

  ##### Validation

  validates_length_of :address, :within => 7..80   validates_format_of :address, :with => /^([^@\s]+)@((?:[-a-z0-9]+\.)+ [a-z]{2,})$/

  ##### Class Methods

  ##### Instance Methods

  def generated_identifier   @generated_identifier ||= generate_identifier   end

  def id_with_generated_identifier   new_record? ? generated_identifier : id_without_generated_identifier   end   alias_method_chain :id, :generated_identifier

  def blank?   address.blank?   end

private

  def generate_identifier(len=10)   chars = ("a".."z").to_a + (1..9).to_a   identifier = ""   1.upto(len){|i| identifier += chars[rand(chars.size-1)].to_s }   identifier   end

end

Note that the EmailAddress model generates an ID for itself if it is a new record. this is done so I can generate urls using named routes and a dom_id for the object on a form where there may be a couple "new" EmailAddresses. For example in a view I would:

<div id ="<%= dom_id(email_address) %>"> <%= link_to "Delete", person_contact_method_url(@person, email_address)   + "?type=email_address", :method => :delete %> </div>[/code] The dom_id would be: email_address_894j5jksl The url would be: /person/0/contact_methods/894j5jksl? type=email_address

class PeopleController < ApplicationController

  helper :contact_methods

  # GET /people   def index   # preload the new form   @person = provider.new

  # set place holder data for the form   @person.set_place_holder_data

  # get all of the contacts with eagerly loaded data     @people = provider.find_roots(:all)

    respond_to do |format|       format.html # index.rhtml       format.xml { render :xml => @people.to_xml }     end   end

  # GET /people/1   def show     @person = provider.find_with_includes(params[:id])

    respond_to do |format|       format.html # show.rhtml       format.xml { render :xml => @person.to_xml }     end   end

  # POST /people   def create   @person = provider.new

    respond_to do |format|       if @person.update_from_params(params[:person])         flash[:notice] = 'Contact was successfully created.'     format.js {}       else     format.js {       render :update do |page|       page[:new_person_form_errors].replace_html error_messages_for(:person)       end     }       end     end   end

  # GET /people/1/edit   def edit     @person = provider.find_and_set_place_holders(params[:id])   end

  # PUT /people/1   def update     @person = provider.find(params[:id])

    respond_to do |format|       if @person.update_from_params(params[:person])         flash[:notice] = 'Contact was successfully updated.'     format.js         format.html { redirect_to people_url }       else         format.html { render :action => "edit" }       end     end   end

private

  def provider   current_account.people   end

end

class ContactMethodsController < ApplicationController

  def new   @object = provider.new   respond_to do |format|     format.js   end   end

  def destroy   if params[:id].match(/^\d+$/)     @object = provider.find(params[:id])     @object.destroy   end

  @object = provider.new   respond_to do |format|     format.js   end   end

private

  def provider     if params[:person_id].eql?('0')     @person = current_account.people.new     @person.set_place_holder_data   end   @person ||= current_account.people.find(params[:person_id])

  case params[:type]     when 'phone_number'     return @person.phone_numbers     when 'email_address'     return @person.email_addresses     when 'address'     return @person.addresses   end   end

end

This maybe a bit confusing, but the problem occurs when I put this code into production. The first time you load the "new" action in the PeopleController it works fine. The second time it gives me a 500 error because the ID has disappeared from the EmailAddress and I am using named route functions to generated urls which require it. At first I though it had something to do with the generated_identifier not being set the second time. Not the case, actually I put a raise statement in the aliased method id_with_generated_identifier which never gets called after the first execution. After hours of debugging I figured out that if I turn off the cache_classes setting in production/environment.rb it works great. Slow ... but great. It seems that the alias_method_chain which creates an alias from id_with_generated_identifier to id is broken after the first execution. I am not sure why this is. Does anyone have an idea why this would be happening? If not, does anyone have a better way of accomplishing this that would allow me to cache my classes again? If more clarification is needed please let me know.

Thanks, Nicholas