--- a/mercurial/patch.py	Sun Oct 14 09:07:43 2018 +0000
+++ b/mercurial/patch.py	Sun Oct 14 09:24:36 2018 +0000
@@ -2480,7 +2480,7 @@
                 endspaces = chomp[len(token):]
             # scan tabs
             for maybetab in tabsplitter.findall(token):
-                if '\t' == maybetab[0]:
+                if b'\t' == maybetab[0:1]:
                     currentlabel = 'diff.tab'
                 else:
                     if changed: