dm_parent_validation_interestingness.rb

=begin
 I was trying to setup some behavior where if
 a new object's parent was not saved, I could
 communicate the errors to the user using the standard model.errors stuff
 and ran into a problem.
 'before :save' does not run before :save, it runs before save_self
 since save looks like this:
 
    chainable do
      def save
        save_parents && save_self && save_children
      end
    end
    
 if the parent objects fail to save, then the before :save 
 and by extension before :valid? calls are never made.
 
=end
require 'rubygems'
require 'dm-core'
require 'dm-validations'

DataMapper.setup(:default,"mysql://root@localhost/testing")

class A
  include DataMapper::Resource
  property :id,Serial
  belongs_to :b
  before :save do
    puts 'before save'
  end
  
  after :save_parents do
    puts 'after save parents'
    if b.errors
      b.errors.each do |error|
        p error.to_s
        errors.add :b,error.to_s
      end
    end
  end
  
  before :valid? do
    puts 'before valid'
  end
end

class B
  include DataMapper::Resource
  has 1, :a
  property :id,Serial
  property :x,String
  validates_present :x
end
DataMapper.auto_migrate!
a = A.new
a.b = B.new
p a.save
p a.errors.on :b
#$ ruby dm_before_valid.rb
#
#after save parents
#false
#[]