Python __subclasses__() not listing subclasses

Question

I cant seem to list all derived classes using the __subclasses__() method. Here\'s my directory layout:

import.py
backends
      __init__.py
            


        

Answer 1

There were no other base.py files. I'm on a WinXP (SP2) with Python 2.6. I added another class to my test.py file called PluginB which used BasePlugin as the base class. When i did

    print PluginA.__mro__
    print PluginB.__mro__

I got:

(<class 'plugina_plugin.PluginA'>, <class 'base.BasePlugin'>, <type 'object'>)
(<class 'backends.digger.test.PluginB'>, <class 'backends.digger.base.BasePlugin'>, <type 'object'>)

As you can see, they're both using the same base plugin but the qualified names are different. This was because in plugina_plugin.py I was importing BasePlugin like this:

from base import BasePlugin

Instead of:

from backends.digger.base import BasePlugin

Fixing this fixed it.

Answer 2

Perhaps the plugins are finding another base.py hiding somewhere (the plugin directory for example).
Run with python -v to see if two different base.py are getting imported

You can also look at PluginA.__mro__ and confirm that the BasePlugin in there is the right one