In PyObject_IsTrue(), don't call function pointers that are NULL

(nb_nonzero, mp_length, sq_length).

diff --git a/Objects/object.c b/Objects/object.c
index 0588fea5061da0608166ff9daa98fb69125a8efb..964c5c59f29e97375dbe05f7bcf15200003d279b 100644 (file)
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -469,11 +469,14 @@ PyObject_IsTrue(v)
        int res;
        if (v == Py_None)
                res = 0;
-       else if (v->ob_type->tp_as_number != NULL)
+       else if (v->ob_type->tp_as_number != NULL &&
+                v->ob_type->tp_as_number->nb_nonzero != NULL)
                res = (*v->ob_type->tp_as_number->nb_nonzero)(v);
-       else if (v->ob_type->tp_as_mapping != NULL)
+       else if (v->ob_type->tp_as_mapping != NULL &&
+                v->ob_type->tp_as_mapping->mp_length != NULL)
                res = (*v->ob_type->tp_as_mapping->mp_length)(v);
-       else if (v->ob_type->tp_as_sequence != NULL)
+       else if (v->ob_type->tp_as_sequence != NULL &&
+                v->ob_type->tp_as_sequence->sq_length != NULL)
                res = (*v->ob_type->tp_as_sequence->sq_length)(v);
        else
                res = 1;