lib/PublicInbox/Mbox.pm | 5 ++---

diff --git a/lib/PublicInbox/Mbox.pm b/lib/PublicInbox/Mbox.pm
index 1f9ac6ec88cfd1a0989a0da5f7d44ab8590230cd..cf93e7dbb64b21cfe57d417bf75902829013512b 100644
--- a/lib/PublicInbox/Mbox.pm
+++ b/lib/PublicInbox/Mbox.pm
@@ -24,11 +24,10 @@
 	# no need for full Email::MIME, here
 	if ($fn =~ /=\?/) {
 		eval { $fn = Encode::decode('MIME-Header', $fn) };
-		$fn = 'no-subject' if $@;
+		return 'no-subject' if $@;
 	}
 	$fn =~ s/^re:\s+//i;
-	$fn = to_filename($fn);
-	$fn eq '' ? 'no-subject' : $fn;
+	$fn eq '' ? 'no-subject' : to_filename($fn);
 }
 
 sub mb_stream {