view: skip ghosts with no direct children

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.

1 files changed, 12 insertions, 3 deletions

diff --git a/lib/PublicInbox/SearchThread.pm b/lib/PublicInbox/SearchThread.pm
index 5774a956..ee35f0d0 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;