bpo-44606: Fix __instancecheck__ and __subclasscheck__ for the union type. (GH-27120)
* Fix issubclass() for None.
E.g. issubclass(type(None), int | None) returns now True.
* Fix issubclass() for virtual subclasses.
E.g. issubclass(dict, int | collections.abc.Mapping) returns now True.
* Fix crash in isinstance() if the check for one of items raises exception.
(cherry picked from commit 81989058de381108dfd0a4255b93d4fb34417002)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
diff --git a/Objects/unionobject.c b/Objects/unionobject.c
index 8435763..bcba0f6 100644
--- a/Objects/unionobject.c
+++ b/Objects/unionobject.c
@@ -67,8 +67,14 @@ union_instancecheck(PyObject *self, PyObject *instance)
if (arg == Py_None) {
arg = (PyObject *)&_PyNone_Type;
}
- if (PyType_Check(arg) && PyObject_IsInstance(instance, arg) != 0) {
- Py_RETURN_TRUE;
+ if (PyType_Check(arg)) {
+ int res = PyObject_IsInstance(instance, arg);
+ if (res < 0) {
+ return NULL;
+ }
+ if (res) {
+ Py_RETURN_TRUE;
+ }
}
}
Py_RETURN_FALSE;
@@ -90,8 +96,17 @@ union_subclasscheck(PyObject *self, PyObject *instance)
Py_ssize_t nargs = PyTuple_GET_SIZE(alias->args);
for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
PyObject *arg = PyTuple_GET_ITEM(alias->args, iarg);
- if (PyType_Check(arg) && (PyType_IsSubtype((PyTypeObject *)instance, (PyTypeObject *)arg) != 0)) {
- Py_RETURN_TRUE;
+ if (arg == Py_None) {
+ arg = (PyObject *)&_PyNone_Type;
+ }
+ if (PyType_Check(arg)) {
+ int res = PyObject_IsSubclass(instance, arg);
+ if (res < 0) {
+ return NULL;
+ }
+ if (res) {
+ Py_RETURN_TRUE;
+ }
}
}
Py_RETURN_FALSE;