clone_class.py

import types
import copy

def clone_class(klass):
    def _exec_body(ns):
        ns_no_slots = {
            k:v for k,v in vars(klass).items()
            if not isinstance(v, types.MemberDescriptorType)
        }
        ns |= copy.deepcopy(ns_no_slots)
        return ns
    return types.new_class(
        name=klass.__name__,
        bases=klass.__bases__,
        kwds={"metaclass": type(klass)},
        exec_body=_exec_body,
    )



if __name__ == "__main__:
    class Meta(type):
        def meta_magic(cls):
            print("magical!")

    class Foo(metaclass=Meta):
        __slots__ = ('x','y')
        @property
        def size(self):
            return 42

    class Bar(Foo):
        state = []
        __slots__ = ('z',)
        def __init__(self, x=1, y=2, z=3):
            self.x = x
            self.y = y
            self.z = z
        @property
        def closed(self):
            return False
    
    BarClone = clone_class(Bar)

    bar = BarClone()
    BarClone.state.append('foo')
    print(BarClone.state, Bar.state)
    BarClone.meta_magic()