From 97c1adf3935234da716d3289b85f72dcd67e90c2 Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Thu, 18 Aug 2016 09:22:23 -0700 Subject: Anti-registration of various ABC methods. - Issue #25958: Support "anti-registration" of special methods from various ABCs, like __hash__, __iter__ or __len__. All these (and several more) can be set to None in an implementation class and the behavior will be as if the method is not defined at all. (Previously, this mechanism existed only for __hash__, to make mutable classes unhashable.) Code contributed by Andrew Barnert and Ivan Levkivskyi. --- Objects/enumobject.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'Objects/enumobject.c') diff --git a/Objects/enumobject.c b/Objects/enumobject.c index c458cfe73d..dae166d5ad 100644 --- a/Objects/enumobject.c +++ b/Objects/enumobject.c @@ -250,6 +250,13 @@ reversed_new(PyTypeObject *type, PyObject *args, PyObject *kwds) return NULL; reversed_meth = _PyObject_LookupSpecial(seq, &PyId___reversed__); + if (reversed_meth == Py_None) { + Py_DECREF(reversed_meth); + PyErr_Format(PyExc_TypeError, + "'%.200s' object is not reversible", + Py_TYPE(seq)->tp_name); + return NULL; + } if (reversed_meth != NULL) { PyObject *res = PyObject_CallFunctionObjArgs(reversed_meth, NULL); Py_DECREF(reversed_meth); @@ -259,8 +266,9 @@ reversed_new(PyTypeObject *type, PyObject *args, PyObject *kwds) return NULL; if (!PySequence_Check(seq)) { - PyErr_SetString(PyExc_TypeError, - "argument to reversed() must be a sequence"); + PyErr_Format(PyExc_TypeError, + "'%.200s' object is not reversible", + Py_TYPE(seq)->tp_name); return NULL; } -- cgit v1.2.1