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--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -3137,6 +3137,7 @@
PyTypeObject *metatype = Py_TYPE(type);
PyObject *meta_attribute, *attribute;
descrgetfunc meta_get;
+ PyObject* res;
if (!PyUnicode_Check(name)) {
PyErr_Format(PyExc_TypeError,
@@ -3158,6 +3159,7 @@
meta_attribute = _PyType_Lookup(metatype, name);
if (meta_attribute != NULL) {
+ Py_INCREF(meta_attribute);
meta_get = Py_TYPE(meta_attribute)->tp_descr_get;
if (meta_get != NULL && PyDescr_IsData(meta_attribute)) {
@@ -3165,10 +3167,11 @@
* writes. Assume the attribute is not overridden in
* type's tp_dict (and bases): call the descriptor now.
*/
- return meta_get(meta_attribute, (PyObject *)type,
- (PyObject *)metatype);
+ res = meta_get(meta_attribute, (PyObject *)type,
+ (PyObject *)metatype);
+ Py_DECREF(meta_attribute);
+ return res;
}
- Py_INCREF(meta_attribute);
}
/* No data descriptor found on metatype. Look in tp_dict of this
@@ -3176,6 +3179,7 @@
attribute = _PyType_Lookup(type, name);
if (attribute != NULL) {
/* Implement descriptor functionality, if any */
+ Py_INCREF(attribute);
descrgetfunc local_get = Py_TYPE(attribute)->tp_descr_get;
Py_XDECREF(meta_attribute);
@@ -3183,11 +3187,12 @@
if (local_get != NULL) {
/* NULL 2nd argument indicates the descriptor was
* found on the target object itself (or a base) */
- return local_get(attribute, (PyObject *)NULL,
- (PyObject *)type);
+ res = local_get(attribute, (PyObject *)NULL,
+ (PyObject *)type);
+ Py_DECREF(attribute);
+ return res;
}
- Py_INCREF(attribute);
return attribute;
}
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2018-03-14-21-42-17.bpo-25750.lxgkQz.rst
@@ -0,0 +1,2 @@
+Fix rare Python crash due to bad refcounting in ``type_getattro()`` if a
+descriptor deletes itself from the class.
|