Can anyone tell me the “proper” way to extend a model provided by an
app engine (or any plugin for that matter).
I’m attempting to extend an app engine model by adding a
has_many :through. So I’ve got lib/myplugin_ext.rb and I’m requiring
that file in evironment.rb. My extension uses class_eval to add the
This works fine in the console for viewing and adding stuff to the
has_many :through association, but in dev mode – after the first
request – if I try to add to the has_many :through, I get “TypeError:
Can’t dup NilClass”.
Because it works in the console but not in development mode after the
first request, this leads me to believe that it’s a weird problem with
the reloader and how I’m extending the class. I’ve tried virtually
everything I can think of (aside from just moving the models from the
app engine into my app directory and modifying it there, which
works…), but I can’t seem to avoid this error any other way.
I tried the “unloadable” suggestion posted here: http://strd6.com/?p=250
Adding unloadable to the app engine model only seemed to make the
situation worse. The app engine model gets reloaded without the
extension at all on subsequent requests.
I isolated the problem in a blank app and posted it here on github:
The stack trace is also available at that repo.
If I’m doin’ it completely wrong, please tell me what would help. Much