--- a/mercurial/repair.py	Tue Dec 03 17:17:57 2019 -0800
+++ b/mercurial/repair.py	Thu Dec 05 11:15:19 2019 -0500
@@ -131,7 +131,7 @@
     cl = repo.changelog
 
     # TODO handle undo of merge sets
-    if isinstance(nodelist, str):
+    if isinstance(nodelist, bytes):
         nodelist = [nodelist]
     striplist = [cl.rev(node) for node in nodelist]
     striprev = min(striplist)