hval: to_filename: return `undef' instead of empty string

[public-inbox.git] / lib / PublicInbox / Hval.pm

diff --git a/lib/PublicInbox/Hval.pm b/lib/PublicInbox/Hval.pm
index 46a839160c3f996e25eb4e0b91b4a1a82fdfabef..e21a64a60e6690636555c2d7dc52473301ba5d25 100644 (file)
--- a/lib/PublicInbox/Hval.pm
+++ b/lib/PublicInbox/Hval.pm
@@ -94,12 +94,12 @@ sub obfuscate_addrs ($$;$) {
 
 # like format_sanitized_subject in git.git pretty.c with '%f' format string
 sub to_filename ($) {
-       my ($s, undef) = split(/\n/, $_[0]);
+       my $s = (split(/\n/, $_[0]))[0] // return; # empty string => undef
        $s =~ s/[^A-Za-z0-9_\.]+/-/g;
        $s =~ tr/././s;
        $s =~ s/[\.\-]+\z//;
        $s =~ s/\A[\.\-]+//;
-       $s
+       $s eq '' ? undef : $s;
 }
 
 # convert a filename (or any string) to HTML attribute