error.txt

ra:timeline[master*]$ ruby wtf.rb 
/Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/associations/one_embedded_proxy.rb:35:in `assign_references': undefined method `_parent_document=' for nil:NilClass (NoMethodError)
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/associations/one_embedded_proxy.rb:19:in `replace'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/associations.rb:41:in `membership='
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/keys.rb:260:in `send'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/keys.rb:260:in `load_from_database'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/bson-1.0.2/lib/../lib/bson/ordered_hash.rb:72:in `each'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/bson-1.0.2/lib/../lib/bson/ordered_hash.rb:72:in `each'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/keys.rb:258:in `load_from_database'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/keys.rb:161:in `initialize'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/dirty.rb:43:in `initialize'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/sci.rb:26:in `initialize'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/keys.rb:62:in `new'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/keys.rb:62:in `load'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/querying/decorator.rb:29:in `first'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/querying.rb:154:in `find_one'
	from /Users/ryan/.rvm/gems/ree-1.8.6-20090610/gems/mongo_mapper-0.8.0/lib/mongo_mapper/plugins/querying.rb:13:in `find'
	from wtf.rb:24

simple_mm_script.rb

require 'rubygems'
require 'mongo_mapper'

MongoMapper.database = 'wtf'

class User
  include MongoMapper::Document
  
  has_one :membership
end

class Membership
  include MongoMapper::EmbeddedDocument

  belongs_to :user
end

User.delete_all

a = User.create :membership => Membership.new
User.find a.id

b = User.create
User.find b.id