(Merge 3.1) 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 b5e86fb..1fe0de5 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -4564,6 +4564,22 @@
with self.assertRaises(AttributeError):
del X.__abstractmethods__
+ def test_proxy_call(self):
+ class FakeStr(object):
+ __class__ = str
+
+ fake_str = FakeStr()
+ # isinstance() reads __class__ on new style classes
+ 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 bb6f5ef..6674c0b 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -9,6 +9,11 @@
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 #10517: After fork(), reinitialize the TLS used by the PyGILState_*
APIs, to avoid a crash with the pthread implementation in RHEL 5. Patch
by Charles-François Natali.
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 9d735a2..135b6d2 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -224,7 +224,8 @@
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 '%.200s' "
"requires a '%.100s' object "
@@ -282,7 +283,8 @@
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 '%.200s' "
"requires a '%.100s' object "
@@ -1046,7 +1048,8 @@
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) {