Validate presence of polymorphic parent

Question

I am developing a Rails 3.2 application with the following models:

class User < ActiveRecord::Base
  # Associations
  belongs_to :authenticatable, polymorphic         


        

Answer 1

You can just move validation to before_save callback and it will work fine:

class User < ActiveRecord::Base
  # Associations
  belongs_to :authenticatable, polymorphic: true

  # Validations
  before_save :check_authenticatable

  def check_authenticatable
    unless authenticatable
      errors[:customizable] << "can't be blank"
      false
    end
  end
end