lib/PublicInbox/Import.pm | 2 +-

diff --git a/lib/PublicInbox/Import.pm b/lib/PublicInbox/Import.pm
index 4c7bbf14678342e2eeaf70af358afa671b822964..5bae69df4d349f1e40a898df0bf3972684eff588 100644
--- a/lib/PublicInbox/Import.pm
+++ b/lib/PublicInbox/Import.pm
@@ -168,7 +168,7 @@ 	binmode $w, ':utf8' or die "binmode :utf8 failed: $!";
 	print $w "commit $ref\nmark :$commit\n",
 		"author $name <$email> $date\n",
 		"committer $self->{ident} ", now2822(), "\n",
-		"data ", (length($subject) + 1), "\n",
+		"data ", (bytes::length($subject) + 1), "\n",
 		$subject, "\n\n" or wfail;
 	binmode $w, ':raw' or die "binmode :raw failed: $!";