hgext/uncommit.py

--- a/hgext/uncommit.py	Sat Mar 17 00:06:14 2018 +0900
+++ b/hgext/uncommit.py	Wed Mar 14 11:16:49 2018 -0700
@@ -166,7 +166,8 @@
 
         with repo.transaction('uncommit'):
             match = scmutil.match(old, pats, opts)
-            newid = _commitfiltered(repo, old, match, opts.get('keep'))
+            allowempty = opts.get('keep') or pats
+            newid = _commitfiltered(repo, old, match, allowempty)
             if newid is None:
                 ui.status(_("nothing to uncommit\n"))
                 return 1