Protect references to tp_descr_get and tp_dict with the appropriate test:

PyType_HasFeature(t, Py_TPFLAGS_HAVE_CLASS).

diff --git a/Objects/classobject.c b/Objects/classobject.c
index cef1894737e6f4ee2415d72fac14a60fd1dcdde2..57de8e9e2113c2e91647f588e82c890f48d27d3a 100644 (file)
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -4,6 +4,9 @@
 #include "Python.h"
 #include "structmember.h"
 
+#define TP_DESCR_GET(t) \
+    (PyType_HasFeature(t, Py_TPFLAGS_HAVE_CLASS) ? (t)->tp_descr_get : NULL)
+
 
 /* Forward */
 static PyObject *class_lookup(PyClassObject *, PyObject *,
@@ -232,7 +235,7 @@ class_getattr(register PyClassObject *op, PyObject *name)
                             PyString_AS_STRING(op->cl_name), sname);
                return NULL;
        }
-       f = v->ob_type->tp_descr_get;
+       f = TP_DESCR_GET(v->ob_type);
        if (f == NULL)
                Py_INCREF(v);
        else
@@ -693,7 +696,7 @@ instance_getattr2(register PyInstanceObject *inst, PyObject *name)
        v = class_lookup(inst->in_class, name, &class);
        if (v != NULL) {
                Py_INCREF(v);
-               f = v->ob_type->tp_descr_get;
+               f = TP_DESCR_GET(v->ob_type);
                if (f != NULL) {
                        PyObject *w = f(v, (PyObject *)inst,
                                        (PyObject *)(inst->in_class));
@@ -2054,18 +2057,20 @@ instancemethod_getattro(PyObject *obj, PyObject *name)
 {
        PyMethodObject *im = (PyMethodObject *)obj;
        PyTypeObject *tp = obj->ob_type;
-       PyObject *descr, *res;
-       descrgetfunc f;
+       PyObject *descr = NULL, *res;
+       descrgetfunc f = NULL;
 
-       if (tp->tp_dict == NULL) {
-               if (PyType_Ready(tp) < 0)
-                       return NULL;
+       if (PyType_HasFeature(tp, Py_TPFLAGS_HAVE_CLASS)) {
+               if (tp->tp_dict == NULL) {
+                       if (PyType_Ready(tp) < 0)
+                               return NULL;
+               }
+               descr = _PyType_Lookup(tp, name);
        }
 
-       descr = _PyType_Lookup(tp, name);
        f = NULL;
        if (descr != NULL) {
-               f = descr->ob_type->tp_descr_get;
+               f = TP_DESCR_GET(descr->ob_type);
                if (f != NULL && PyDescr_IsData(descr))
                        return f(descr, obj, (PyObject *)obj->ob_type);
        }