From: Guido van Rossum <guido@python.org>
Date: Tue, 21 Jul 1998 21:56:41 +0000 (+0000)
Subject: When comparing objects, always check that tp_compare is not NULL
X-Git-Tag: v1.5.2a1~278
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b4db1944c4392cb1510f01dcd2b10da6949b83fc;p=thirdparty%2FPython%2Fcpython.git

When comparing objects, always check that tp_compare is not NULL
before calling it.  This check was there when the objects were of the
same type *before* coercion, but not if they initially differed but
became the same *after* coercion.
---

diff --git a/Objects/object.c b/Objects/object.c
index 2428cc9331ca..b62477a812f3 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -312,14 +312,18 @@ PyObject_Compare(v, w)
 	if ((vtp = v->ob_type) != (wtp = w->ob_type)) {
 		char *vname = vtp->tp_name;
 		char *wname = wtp->tp_name;
-		if (vtp->tp_as_number != NULL &&
-				wtp->tp_as_number != NULL) {
+		if (vtp->tp_as_number != NULL && wtp->tp_as_number != NULL) {
 			int err;
 			err = PyNumber_CoerceEx(&v, &w);
 			if (err < 0)
 				return -1;
 			else if (err == 0) {
-				int cmp = (*v->ob_type->tp_compare)(v, w);
+				int cmp;
+				vtp = v->ob_type;
+				if (vtp->tp_compare == NULL)
+					cmp = (v < w) ? -1 : 1;
+				else
+					cmp = (*vtp->tp_compare)(v, w);
 				Py_DECREF(v);
 				Py_DECREF(w);
 				return cmp;