hgext/show.py

--- a/hgext/show.py	Mon Jul 03 21:12:04 2017 -0700
+++ b/hgext/show.py	Mon Jul 03 21:18:32 2017 -0700
@@ -233,7 +233,7 @@
     try:
         cmdutil.findcmd('rebase', commands.table)
         haverebase = True
-    except error.UnknownCommand:
+    except (error.AmbiguousCommand, error.UnknownCommand):
         haverebase = False
 
     # TODO use templating.