New submission from Géry <gery.o...@gmail.com>: A use case of one-argument `super` (aka unbound `super`) is Guido van Rossum’s autosuper described in his 2002 article [*Unifying types and classes in Python 2.2*](https://www.python.org/download/releases/2.2.3/descrintro/#cooperation).
It works with functions, but not with `classmethod` as Michele Simionato noted in his 2008 article [*Things to Know About Python Super*](https://www.artima.com/weblogs/viewpost.jsp?thread=236278). I suggest fixing this by updating the method `super.__get__` to bind an unbound `super` object to the argument `owner` when there is no argument `instance` to bind to. Here is the patch applied to the C function [super_descr_get](https://github.com/python/cpython/blob/v3.9.5/Objects/typeobject.c#L8029-L8061) in Objects/typeobject.c, given in pure Python for better readability: ```python def __get__(self, instance, owner=None): if instance is None and owner is None: raise TypeError('__get__(None, None) is invalid') - if instance is None or self.__self__ is not None: + if self.__self__ is not None: return self + if instance is None: + return type(self)(self.__thisclass__, owner) return type(self)(self.__thisclass__, instance) ``` Demonstration: ```python >>> class A: ... def f(self): return 'A.f' ... @classmethod ... def g(cls): return 'A.g' ... >>> class B(A): ... def f(self): return 'B.f ' + self.__super.f() ... @classmethod ... def g(cls): return 'B.g ' + cls.__super.g() ... >>> B._B__super = super(B) # the CURRENT broken version of super >>> print(B().f()) # function succeeds (instance binding) B.f A.f >>> print(B.g()) # classmethod fails (no binding) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "<stdin>", line 4, in g AttributeError: 'super' object has no attribute 'g' >>> B._B__super = super(B) # the PROPOSED fixed version of super >>> print(B().f()) # function succeeds (instance binding) B.f A.f >>> print(B.g()) # classmethod succeeds (class binding) B.g A.g ``` ---------- components: Interpreter Core messages: 393326 nosy: maggyero priority: normal severity: normal status: open title: Add class binding to unbound super objects for allowing autosuper with class methods type: enhancement versions: Python 3.10, Python 3.11, Python 3.9 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue44090> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
