[Python-checkins] cpython (3.1): Issue #9756: When calling a method descriptor or a slot wrapper descriptor, the

Sun May 1 23:33:17 CEST 2011

http://hg.python.org/cpython/rev/c5e6f997730e
changeset: 69741:c5e6f997730e
branch: 3.1
parent: 69733:c57fdce01eb8
user: Victor Stinner <victor.stinner at haypocalc.com>
date: Sun May 01 23:19:15 2011 +0200
summary:
 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).
files:
 Lib/test/test_descr.py | 16 ++++++++++++++++
 Misc/NEWS | 5 +++++
 Objects/descrobject.c | 9 ++++++---
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
--- 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
--- 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
--- 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) {
-- 
Repository URL: http://hg.python.org/cpython
