cannot do mass_assignment when inherited class ?

I got the following error when trying to create the elibrary instance

(rdb:21) @elibrary = Elibrary.new(params[:elibrary]) RuntimeError Exception: Declare either attr_protected or attr_accessible for Elibrary, but not both.

params : "elibrary"=>{"title"=>"bingo three", "short_description"=>"something new", "description"=>"<p>fsdfgdsg</

"}

Elibrary is declared as inherited from MediaItem, and attr are declared accessible in MediaItem....

class MediaItem < ActiveRecord::Base   belongs_to :media_container   # Behaviours   acts_as_nested_set    attr_accessible :title, :short_description, :description ...

class Elibrary < MediaItem end

when @elibrary = Elibrary.new, then assigning attributes to @elibrary, save is OK.....

1- even duplicatiing the attr_accessible in both classes doesn't help 2- acts_as_nested_set brought additional fields .. ant issue with it ?

The error is somewhere in your class declaration, but the message you're getting doesn't appear until you run attributes=. I'd look at the other plugins you're using, as somebody's calling attr_protected on MediaItem.

--Mat Jones