--- a/mercurial/hgweb/common.py	Tue Dec 03 17:17:57 2019 -0800
+++ b/mercurial/hgweb/common.py	Thu Dec 05 11:15:19 2019 -0500
@@ -191,7 +191,7 @@
         return
 
     fpath = os.path.join(*fname.split(b'/'))
-    if isinstance(directory, str):
+    if isinstance(directory, bytes):
         directory = [directory]
     for d in directory:
         path = os.path.join(d, fpath)