--- a/mercurial/pvec.py	Tue Dec 03 17:17:57 2019 -0800
+++ b/mercurial/pvec.py	Thu Dec 05 11:15:19 2019 -0500
@@ -183,7 +183,7 @@
 
 class pvec(object):
     def __init__(self, hashorctx):
-        if isinstance(hashorctx, str):
+        if isinstance(hashorctx, bytes):
             self._bs = hashorctx
             self._depth, self._vec = _split(util.b85decode(hashorctx))
         else: