--- a/mercurial/hg.py	Fri Apr 24 17:00:18 2009 -0500
+++ b/mercurial/hg.py	Fri Apr 24 18:17:42 2009 +0200
@@ -25,7 +25,7 @@
 
     url, branch = url.split('#', 1)
     checkout = revs and revs[-1] or branch
-    return url, revs + [branch], checkout
+    return url, (revs or []) + [branch], checkout
 
 schemes = {
     'bundle': bundlerepo,