get true `dict` if `dict` was overridden

Is it possible to get object's true __dict__ if __dict__ was overridden? Are there simpler solutions than the ones below?

I came across this example where __dict__ was overridden and got curious. I thought python is using __dict__ to recognize object's attributes but turned out it can be overridden and attributes will still work. So, the original __dict__ is still out there.

class MyClass:
    __dict__ = {}
obj = MyClass()
obj.hacky = 5
# 5, {}
print(obj.hacky, obj.__dict__)

Solution

Looking for a solution I've found this. Though it is a bit hacky but it works - it's swapping __class__ to access the original __dict__ and then swapping it back. It works even with __class__, __setattr__ and __dict__ all used for something else.

def get_true_dict(obj: object) -> dict:
    cls = type(obj)
    newcls = type('',(),{}) # one line empty class
    # __class__ is <attribute '__class__' of 'object' objects>
    object.__dict__['__class__'].__set__(obj, newcls)
    # obj.__class__ = newcls # works only if `__class__` and `__setattr__` are not "bad"
    res = obj.__dict__
    # no safety as class is fine
    obj.__class__ = cls
    return res

# normal
class X: ...
x = X()
x.a = 42
assert get_true_dict(x) is x.__dict__

# blocked setattr and __dict__ and __class__
d = {}
class X:
    __dict__ = d
    __class__ = 42
    __setattr__ = lambda *_: 1/0
x = X()
assert x.__dict__ is d
assert get_true_dict(x) is not x.__dict__

d = get_true_dict(x)
d['a'] = 42
assert x.a == 42
d['b'] = 24
assert x.b == 24
print(d)

There is also even more obscure option to get it by using ctypes and offsets but it seems to work only if obj.__dict__ was already accessed before and otherwise returns ValueError: PyObject is NULL. Unless there is some workaround to initialize __dict__, this solution's flaw defies the entire purpose of the get_true_dict method.

def get_true_dict(obj: object) -> dict:
    import ctypes
    # -24 = -48 + 24
    offset = type(obj).__dictoffset__ + obj.__sizeof__()
    res = ctypes.py_object.from_address(id(obj) + offset)
    return res.value

class X: ...
x = X()
x.__dict__ # <<< comment this and it will change the behaviour and will result in
# ValueError: PyObject is NULL too

x.a = 42
assert get_true_dict(x) is x.__dict__

d = {}
class X:
    __dict__ = d
x = X()
x.a = 42
assert x.__dict__ is d
# ValueError: PyObject is NULL
assert get_true_dict(x) is not x.__dict__
d = get_true_dict(x)

PS Code snippets by @denballakh

get true `__dict__` if `__dict__` was overridden

get true `dict` if `dict` was overridden