How do I dynamically add mixins as base classes without getting MRO errors?

Question

Say I have a class A, B and C.

Class A and B are both mixin classes for Class C.

Answer 1

There is a simple workaround: Create a helper-class, with a nice name, like PluginBase. And use that the inherit of, instead of object.

This makes the code more readable (imho) and it circumstances the bug.

class PluginBase(object): pass
class ServerBase(object): pass

class pluginA(PluginBase): "Now it is clearly a plugin class"
class pluginB(PluginBase): "Another plugin"

class Server1(ServerBase, pluginA, pluginB): "This works"
class Server2(ServerBase): pass
Server2.__base__ += (PluginA,) # This also works

As note: Probably you don't need the factory; it's needed in C++, but hardly in Python