lib/PublicInbox/ViewVCS.pm | 2 +-

diff --git a/lib/PublicInbox/ViewVCS.pm b/lib/PublicInbox/ViewVCS.pm
index eecc51e673b2aad8ad8fbfbca21326ed895be7b6..d67b5eb41dc20e455a74d4a6b7472d37b285e2bf 100644
--- a/lib/PublicInbox/ViewVCS.pm
+++ b/lib/PublicInbox/ViewVCS.pm
@@ -110,7 +110,7 @@ 		return html_page($ctx, 500, \$log);
 	}
 
 	my $binary = index($$blob, "\0") >= 0;
-	if ($fn) {
+	if (defined $fn) {
 		my $h = [ 'Content-Length', $size, 'Content-Type' ];
 		push(@$h, ($binary ? 'application/octet-stream' : 'text/plain'));
 		return delete($ctx->{-wcb})->([200, $h, [ $$blob ]]);