mercurial/dirstate.py

--- a/mercurial/dirstate.py	Wed Feb 02 13:51:22 2011 +0100
+++ b/mercurial/dirstate.py	Fri Feb 04 09:17:07 2011 +0100
@@ -508,7 +508,7 @@
             if files[i] < subpath:
                 i += 1
                 continue
-            while files and files[i].startswith(subpath):
+            while i < len(files) and files[i].startswith(subpath):
                 del files[i]
             j += 1