view: allow for missing In-Reply-To mapping

Because buggy mail clients exist and generate invalid
In-Reply-To headers we cannot handle across the board...

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index ed3c96e80d6ec5297abbae0d1c523e515a42963d..373545a2fadc181607d9946d9a5c10725f4e038c 100644 (file)
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -208,8 +208,8 @@ sub _th_index_lite {
        my $nr_s = 0;
        my $level = $map->[4];
        my $idx = $map->[3];
-       if (defined $irt) {
-               my $irt_map = $mapping->{$irt};
+       my $irt_map = $mapping->{$irt} if defined $irt;
+       if (defined $irt_map) {
                my $siblings = $irt_map->[0];
                $nr_s = scalar(@$siblings) - 1;
                $rv .= $pad . $irt_map->[1];