Update position when scope changes

[chief]

In update, position remains the same when scope changes. I think that a solution should be to trigger add_to_list_bottom but I can't think of any global way, especially in complex scope cases. When it is just a field I use something like this

class TodoItem < ActiveRecord::Base
    belongs_to :todo_list
    acts_as_list :scope => :todo_list
    before_update :change_position

   def change_position
     add_to_list_bottom if todo_list_id_changed?
   end
 end

Is there a better way?

[swanandp]

The use case here is when you move an item from one list to another. Thats a good use case and worth as feature. Let me think over this and get back to you.

[narath]

I would also find this useful, since I am using this with acts_as_tree as well and this needs this functionality.
Also discussed (from 2009 though) at http://ramblings.gibberishcode.net/archives/one-activerecord-model-acting-as-a-list-and-tree/33

[swanandp]

Ah, I forgot all about this.

[swanandp]

There is no sure way of doing this, since you cannot predict what behavior is intended. We can however accept a block as callbacks or hooks.