accepts_nested_attributes_for on has_many does not update or delete if you also set validates_associated

Tested to be a problem in Rails 2.3.8 and working in Rails 2.3.5

If you have a has_many association with validation and then try to update that association with update_attributes on a newly loaded parent object, the validation will overload the objects updated in memory before the save.
Example:

 class Address < ActiveRecord::Base
  belongs_to :contact
  validates_inclusion_of :is_current, :in => [true, false], :allow_nil => true  #any validation will do 
 end







 class Contact < ActiveRecord::Base
   has_many :addresses, :dependent => :destroy
   validates_associated :addresses    

   accepts_nested_attributes_for :addresses, :allow_destroy => true
 end







 #now create a new contact with an address
 company = Contact.create :name => "test"
 newaddress = company.addresses.create :city => "Austin", :is_current => true
 #now reload the company from the db
 company = Contact.find company.id
 #now update attributes
 company.update_attributes(:addresses_attributes => [{:id => newaddress.id, :city => "Dallas",  :is_current => true }]
 #now check the address city
 company.addresses.first.city
 #Will print out Austin

This is because the code in Rails 2.3.8 does not load the addresses association for the nested attributes update. Instead it tries to be clever and it loads only the objects for which it has IDs. This saves time, but when validation runs in sees that company.addresses.loaded? is false and it reloads the association, and wipes out the changes.
In activerecord/lib/active_record/nested_attributes.rb the code:

 existing_records = if association.loaded?

     association.to_a
   else
     attribute_ids = attributes_collection.map {|a| a['id'] || a[:id] }.compact
     attribute_ids.present? ? association.all(:conditions => {association.primary_key => attribute_ids}) : []
   end</code>

Seems to be the problem. If I just change it to

 existing_records = association.to_a

I have no problems.
In Rails 2.3.5 when it loops over the attributes array it uses this code to find the object

 existing_record = send(association_name).detect { |record| record.id.to_s == attributes['id'].to_s }

This will load the association the first time the detect is run, and avoid the problem with validation.