Stupid spelling mistake in a variable name.
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -654,7 +654,7 @@ def clone(ui, source, dest=None, **opts)
repo = hg.repository(ui, dest)
else:
- rev = None
+ revs = None
if opts['rev']:
if not other.local():
raise util.Abort("clone -r not supported yet for remote repositories.")