--- a/hgext/zeroconf/Zeroconf.py	Thu Nov 21 15:46:35 2019 -0500
+++ b/hgext/zeroconf/Zeroconf.py	Fri Nov 22 21:42:04 2019 +0900
@@ -1191,7 +1191,11 @@
                 list.append(b'='.join((key, suffix)))
             for item in list:
                 result = b''.join(
-                    (result, struct.pack(b'!c', chr(len(item))), item)
+                    (
+                        result,
+                        struct.pack(b'!c', pycompat.bytechr(len(item))),
+                        item,
+                    )
                 )
             self.text = result
         else: