Issue #9756: When calling a method descriptor or a slot wrapper descriptor, the
check of the object type doesn't read the __class__ attribute anymore. Fix a
crash if a class override its __class__ attribute (e.g. a proxy of the str
type).
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index bd88f45..aafe428 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -4235,6 +4235,22 @@
with self.assertRaises(AttributeError):
del X.__abstractmethods__
+ def test_proxy_call(self):
+ class FakeStr:
+ __class__ = str
+
+ fake_str = FakeStr()
+ # isinstance() reads __class__
+ self.assertTrue(isinstance(fake_str, str))
+
+ # call a method descriptor
+ with self.assertRaises(TypeError):
+ str.split(fake_str)
+
+ # call a slot wrapper descriptor
+ with self.assertRaises(TypeError):
+ str.__add__(fake_str, "abc")
+
class DictProxyTests(unittest.TestCase):
def setUp(self):
diff --git a/Misc/NEWS b/Misc/NEWS
index b4ba3b6..41bda2a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,11 @@
Core and Builtins
-----------------
+- Issue #9756: When calling a method descriptor or a slot wrapper descriptor,
+ the check of the object type doesn't read the __class__ attribute anymore.
+ Fix a crash if a class override its __class__ attribute (e.g. a proxy of the
+ str type).
+
- Issue #6780: fix starts/endswith error message to mention that tuples are
accepted too.
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 5f118ce..9eda4bd 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -226,7 +226,8 @@
return NULL;
}
self = PyTuple_GET_ITEM(args, 0);
- if (!PyObject_IsInstance(self, (PyObject *)(descr->d_type))) {
+ if (!_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
+ (PyObject *)(descr->d_type))) {
PyErr_Format(PyExc_TypeError,
"descriptor '%V' "
"requires a '%.100s' object "
@@ -284,7 +285,8 @@
return NULL;
}
self = PyTuple_GET_ITEM(args, 0);
- if (!PyObject_IsInstance(self, (PyObject *)(descr->d_type))) {
+ if (!_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
+ (PyObject *)(descr->d_type))) {
PyErr_Format(PyExc_TypeError,
"descriptor '%V' "
"requires a '%.100s' object "
@@ -1065,7 +1067,8 @@
assert(PyObject_TypeCheck(d, &PyWrapperDescr_Type));
descr = (PyWrapperDescrObject *)d;
- assert(PyObject_IsInstance(self, (PyObject *)(descr->d_type)));
+ assert(_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
+ (PyObject *)(descr->d_type)));
wp = PyObject_GC_New(wrapperobject, &wrappertype);
if (wp != NULL) {