Found bug in utils.sortBy, mentioned by Tim Peters on Python-dev. Fixed, and tested.

src/utils.py

@@ -323,10 +323,10 @@ def be(i):
 def sortBy(f, L, cmp=cmp):
     """Uses the decorate-sort-undecorate pattern to sort L by function f."""
     for (i, elt) in enumerate(L):
-        L[i] = (f(elt), elt)
+        L[i] = (f(elt), i, elt)
     L.sort(cmp)
     for (i, elt) in enumerate(L):
-        L[i] = L[i][1]
+        L[i] = L[i][2]
 
 def mktemp(suffix=''):
     """Gives a decent random string, suitable for a filename."""

test/test_utils.py

@@ -177,6 +177,9 @@ class UtilsTest(unittest.TestCase):
         self.assertEqual(L, ['z', 'AD', 'abc'])
         utils.sortBy(str.lower, L)
         self.assertEqual(L, ['abc', 'AD', 'z'])
+        L = ['supybot', 'Supybot']
+        utils.sortBy(str.lower, L)
+        self.assertEqual(L, ['supybot', 'Supybot'])
         
     def testNItems(self):
         self.assertEqual(utils.nItems(1, 'tool', 'crazy'), '1 crazy tool')