--- a/mercurial/archival.py	Thu Apr 19 17:52:42 2007 +0200
+++ b/mercurial/archival.py	Tue Apr 24 10:44:13 2007 -0700
@@ -44,7 +44,8 @@
         if isinstance(dest, str):
             self.z = tarfile.open(dest, mode='w:'+kind)
         else:
-            self.z = tarfile.open(mode='w|'+kind, fileobj=dest)
+            # Python 2.5-2.5.1 have a regression that requires a name arg
+            self.z = tarfile.open(name='', mode='w|'+kind, fileobj=dest)
 
     def addfile(self, name, mode, data):
         i = tarfile.TarInfo(self.prefix + name)