[PATCH 5/7] view: skip ghosts with no direct children

[Eric Wong <e@80x24.org>]

Otherwise, a malicious or broken client could populate the
thread skeleton with invalid References.  We only care about
ghosts which messages correctly refer to, not totally bogus ones
which may be the result of long line or token truncation +
wrapping in MUA headers.
---
 lib/PublicInbox/SearchThread.pm | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/lib/PublicInbox/SearchThread.pm b/lib/PublicInbox/SearchThread.pm
index 5774a95..ee35f0d 100644
--- a/lib/PublicInbox/SearchThread.pm
+++ b/lib/PublicInbox/SearchThread.pm
@@ -33,7 +33,8 @@ sub thread {
 	my $self = shift;
 	_add_message($self, $_) foreach @{$self->{messages}};
 	my $id_table = delete $self->{id_table};
-	$self->{rootset} = [ grep { !delete $_->{parent} } values %$id_table ];
+	$self->{rootset} = [ grep {
+		!delete($_->{parent}) && $_->visible } values %$id_table ];
 }
 
 sub _get_cont_for_id ($$) {
@@ -133,15 +134,23 @@ sub has_descendent {
 	0;
 }
 
+# Do not show/keep ghosts iff they have no children.  Sometimes
+# a ghost Message-ID is the result of a long header line
+# being folded/mangled by a MUA, and not a missing message.
+sub visible ($) {
+	my ($self) = @_;
+	$self->{smsg} || scalar values %{$self->{children}};
+}
+
 sub order_children {
 	my ($cur, $ordersub) = @_;
 
-	my %seen = ($cur => 1);
+	my %seen = ($cur => 1); # self-referential loop prevention
 	my @q = ($cur);
 	while (defined($cur = shift @q)) {
 		my $c = $cur->{children}; # The hashref here...
 
-		$c = [ grep { !$seen{$_}++ } values %$c ]; # spot/break loops
+		$c = [ grep { !$seen{$_}++ && visible($_) } values %$c ];
 		$c = $ordersub->($c) if scalar @$c > 1;
 		$cur->{children} = $c; # ...becomes an arrayref
 		push @q, @$c;
-- 
EW