From 49cd68fb1ed4cbaf109308c0a7c8c1efcf6f3775 Mon Sep 17 00:00:00 2001 From: Ken Jin <28750310+Fidget-Spinner@users.noreply.github.com> Date: Sun, 3 Jan 2021 00:19:15 +0800 Subject: [PATCH] bpo-42195: Disallow isinstance/issubclass for subclasses of genericaliases in Union (GH-24059) Previously this didn't raise an error. Now it will: ```python from collections.abc import Callable isinstance(int, list | Callable[..., str]) ``` Also added tests in Union since there were previously none for stuff like ``isinstance(list, list | list[int])`` either. Backport to 3.9 not required. Automerge-Triggered-By: GH:gvanrossum --- Lib/test/test_types.py | 10 ++++++++++ Objects/unionobject.c | 2 +- 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py index 83196ad3c17..d8a48ce36f6 100644 --- a/Lib/test/test_types.py +++ b/Lib/test/test_types.py @@ -737,6 +737,16 @@ class TypesTests(unittest.TestCase): with self.assertRaises(ZeroDivisionError): list[int] | list[bt] + union_ga = (int | list[str], int | collections.abc.Callable[..., str], + int | d) + # Raise error when isinstance(type, type | genericalias) + for type_ in union_ga: + with self.subTest(f"check isinstance/issubclass is invalid for {type_}"): + with self.assertRaises(TypeError): + isinstance(list, type_) + with self.assertRaises(TypeError): + issubclass(list, type_) + def test_ellipsis_type(self): self.assertIsInstance(Ellipsis, types.EllipsisType) diff --git a/Objects/unionobject.c b/Objects/unionobject.c index 32aa5078afc..05350363eed 100644 --- a/Objects/unionobject.c +++ b/Objects/unionobject.c @@ -34,7 +34,7 @@ is_generic_alias_in_args(PyObject *args) { Py_ssize_t nargs = PyTuple_GET_SIZE(args); for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) { PyObject *arg = PyTuple_GET_ITEM(args, iarg); - if (Py_TYPE(arg) == &Py_GenericAliasType) { + if (PyObject_TypeCheck(arg, &Py_GenericAliasType)) { return 0; } }