gistfile1.txt

class Person < ActiveRecord::Base
  attr_accessor :dont_set_name

  def name
    @name
  end

  def name=(attr)
    @name = attr unless dont_set_name
  end
end

a = Person.new
a.attributes = {name: 'George', dont_set_name: true}
a.name
#=> 'George'

a = Person.new
a.attributes = {dont_set_name: true, name: 'George'}
a.name
#=> nil