nested form, embedded docs, mongoid 2.2.0 problem

Question

I cant seem to find answer for this here or with the google, any help would be awesome. The Building saves correctly, but the embedded doc PriorityArea doesnt get updated... I want to eventually have it ajax a new form for new priority areas evenutally, but need it to update first.

Mongoid::Errors::InvalidFind in BuildingsController#update

Calling Document#find with nil is invalid

class Building
  include Mongoid::Document
  embeds_many :priority_areas
  accepts_nested_attributes_for :priority_areas, :allow_destroy => true, :autosave => true
end

class PriorityArea
  include Mongoid::Document
  embedded_in :building, :inverse_of => :priority_areas
end

#view

= form_for [@customer, @building] do |f|
  ...
  ...
  = f.fields_for :priority_areas do |pa|
    = f.name
    ...
    ...

#controller

@building.update_attributes(params[:building])

It correctly yeilds the correct data from the db, but fails to error above on building#update. Any help is greatly appreciated.

---

update in the building#update im puts params[:building][:priority_areas_attributes].to_yaml

which yeilds

--- !map:ActiveSupport::HashWithIndifferentAccess 
"0": !map:ActiveSupport::HashWithIndifferentAccess 
name: area 51
location: near front door
notes: ""
priority: "1"
id: ""
"1": !map:ActiveSupport::HashWithIndifferentAccess 
name: area 52
location: near rear door
notes: ""
priority: "2"
id: ""

im guessing the problem is the null id:""

Answer 1

The problem was the null id it needed to have an ObjectId to work correctly. stupid error on my part.