Index: Objects/listobject.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Objects/listobject.c,v
retrieving revision 2.220
diff -u -r2.220 listobject.c
--- Objects/listobject.c	8 Aug 2004 21:21:18 -0000	2.220
+++ Objects/listobject.c	9 Aug 2004 05:23:27 -0000
@@ -2186,9 +2186,7 @@
 		if (stop < 0)
 			stop = 0;
 	}
-	else if (stop > self->ob_size)
-		stop = self->ob_size;
-	for (i = start; i < stop; i++) {
+	for (i = start; i < stop && i < self->ob_size; i++) {
 		int cmp = PyObject_RichCompareBool(self->ob_item[i], v, Py_EQ);
 		if (cmp > 0)
 			return PyInt_FromLong((long)i);
Index: Lib/test/list_tests.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/list_tests.py,v
retrieving revision 1.2
diff -u -r1.2 list_tests.py
--- Lib/test/list_tests.py	18 Jan 2004 21:03:23 -0000	1.2
+++ Lib/test/list_tests.py	9 Aug 2004 05:23:27 -0000
@@ -311,6 +311,18 @@
         self.assertRaises(ValueError, a.index, 2, 0, 4)
         self.assertEqual(a, self.type2test([-2, -1, 0, 1, 2]))
 
+        # Test modifying the list during index's iteration
+        class EvilCmp:
+            def __init__(self, victim):
+                self.victim = victim
+            def __eq__(self, other):
+                del self.victim[:]
+                return False
+        a = self.type2test()
+        a[:] = [EvilCmp(a) for _ in xrange(100)]
+        # This used to seg fault before listobject.c 2.221
+        self.assertRaises(ValueError, a.index, None)
+
     def test_reverse(self):
         u = self.type2test([-2, -1, 0, 1, 2])
         u2 = u[:]