python 链式调用 合并 __setattr__ __getattribute__ in nested object()

使用场景：bpy.types.Scene与bpy.context.scene部分功能重叠。

def Get(obj, attr: str | Sequence[str], root=False):
    """injected recursive getattr, could pollute objects on chain in whole session"""
    IS_STR = isinstance(attr, str)
    if IS_STR and attr.startswith("__") and attr != "__getattribute__":
        return object.__getattribute__(obj, attr)
    E: Exception | None = None
    objs = obj if root else (obj,)
    for i, o in enumerate(objs):
        at = attr if IS_STR else attr[i]
        try:
            obj_inject = getattr(o, at)
            setattr(obj_inject, "__getattribute__", Get)
            return obj_inject
        except AttributeError as e:
            if " object attribute '__getattribute__' is read-only" in str(e):
                return obj_inject
            E = e
    if E:
        raise E
    else:
        raise

class A:
    att = True
class B:
    at = False
if __name__ == "__main__":
    at = Get([A, B], "at", root=True)
    print("😄", at)

等价于:

A.at # no attr named 'at'
B.at