--- a/Objects/stringobject.c	Sun Feb 24 02:40:58 2008 +0000
+++ b/Objects/stringobject.c	Sun Feb 24 03:17:21 2008 +0000
@@ -4585,6 +4585,7 @@
 			int prec = -1;
 			int c = '\0';
 			int fill;
+			int isnumok;
 			PyObject *v = NULL;
 			PyObject *temp = NULL;
 			char *pbuf;
@@ -4786,23 +4787,52 @@
 			case 'X':
 				if (c == 'i')
 					c = 'd';
-				if (PyLong_Check(v)) {
-					int ilen;
-					temp = _PyString_FormatLong(v, flags,
-						prec, c, &pbuf, &ilen);
-					len = ilen;
-					if (!temp)
-						goto error;
-					sign = 1;
+				isnumok = 0;
+				if (PyNumber_Check(v)) {
+					PyObject *iobj=NULL;
+
+					if (PyInt_Check(v) || (PyLong_Check(v))) {
+						iobj = v;
+						Py_INCREF(iobj);
+					}
+					else {
+						iobj = PyNumber_Int(v);
+						if (iobj==NULL) iobj = PyNumber_Long(v);
+					}
+					if (iobj!=NULL) {
+						if (PyInt_Check(iobj)) {
+							isnumok = 1;
+							pbuf = formatbuf;
+							len = formatint(pbuf,
+									sizeof(formatbuf),
+									flags, prec, c, iobj);
+							Py_DECREF(iobj);
+							if (len < 0)
+								goto error;
+							sign = 1;
+						}
+						else if (PyLong_Check(iobj)) {
+							int ilen;
+							
+							isnumok = 1;
+							temp = _PyString_FormatLong(iobj, flags,
+								prec, c, &pbuf, &ilen);
+							Py_DECREF(iobj);
+							len = ilen;
+							if (!temp)
+								goto error;
+							sign = 1;
+						}
+						else {
+							Py_DECREF(iobj);
+						}
+					}
 				}
-				else {
-					pbuf = formatbuf;
-					len = formatint(pbuf,
-							sizeof(formatbuf),
-							flags, prec, c, v);
-					if (len < 0)
-						goto error;
-					sign = 1;
+				if (!isnumok) {
+					PyErr_Format(PyExc_TypeError, 
+					    "%%%c format: a number is required, "
+					    "not %.200s", c, Py_TYPE(v)->tp_name);
+					goto error;
 				}
 				if (flags & F_ZERO)
 					fill = '0';