Validate loaded_#{association}? collecting @changed_attributes to avo…

…id SystemStackError: stack level too deep for mutual delegation beetween models

lib/delegates_attributes_to.rb

@@ -80,7 +80,12 @@ module InstanceMethods
  def changed_attributes_with_associations
  result = {}
  self.class.dirty_associations.each do |association, attributes|
- association_changed_attributes = send(association).try(:changed_attributes) || {}
+ # If association isn't loaded yet it isn't changed at all. So we skip it.
+ # If we don't skip it and have mutual delegation beetween 2 models 
+ # we get SystemStackError: stack level too deep while trying to load 
+ # a chain like user.profile.user.profile.user.profile...
+ next unless send("loaded_#{association}?")
+ association_changed_attributes = send(association).send(:changed_attributes) || {}
  result.merge! association_changed_attributes.slice(*attributes)
  end
  changed_attributes_without_associations.merge!(result)

spec/model/mutual_delegation_spec.rb

@@ -0,0 +1,28 @@
+require File.join(File.dirname(__FILE__), '..', 'spec_helper')
+
+describe DelegatesAttributesTo, 'with mutual delegation' do
+
+ before :all do
+ UserNoDefault.has_one :profile, :foreign_key => 'user_id'
+ UserNoDefault.delegates_attributes_to :profile
+
+ Profile.belongs_to :user, :class_name => 'UserNoDefault', :foreign_key => 'user_id'
+ Profile.delegates_attributes_to :user
+ end
+
+ before :each do
+ @user = UserDefault.new
+ @user.about = "I'm Bob"
+ @user.profile.username = "bob"
+ @user.save!
+ end
+
+ describe "#save" do 
+ it "should save and do not raise SystemStackError: stack level too deep" do
+ @user = UserDefault.find(@user.id)
+ @user.should_not be_changed
+ @user.profile.should_not be_changed
+ @user.save
+ end
+ end
+end