gistfile1.rb

require 'rubygems'
require 'mongo_mapper'
require 'pp'

class Person
  include MongoMapper::Document
  
  key :name, String, :default => 'John Doe'
end

p = Person.new
pp p # name is 'John Doe' - as exptected
p.name = nil
pp p # name is still 'John Doe' - shouldn't it be nil?
p.name = '' # name is ''  - as exptected
pp p
p.name = 'Adam'
pp p # name is 'Adam'  - as exptected
p.name = nil
pp p # name is 'John Doe' -  shouldn't it be nil?