--- a/mercurial/commands.py	Thu Feb 16 20:33:14 2023 +0100
+++ b/mercurial/commands.py	Tue Feb 14 11:56:02 2023 -0500
@@ -7472,6 +7472,9 @@
                 )
         node = logcmdutil.revsingle(repo, rev_).node()
 
+        if node is None:
+            raise error.InputError(_(b"cannot tag working directory"))
+
         if not message:
             # we don't translate commit messages
             message = b'Added tag %s for changeset %s' % (