search: preserve References: order in document data

We need proper ordering of References to thread messages
correctly.  We would lose this order if we load the terms
from the database, so set it directly document data.

Do not bother with a separate In-Reply-To, since Mail::Thread
just merges the IRT into References.  This bumps our schema
version once again.

1 files changed, 11 insertions, 12 deletions

diff --git a/lib/PublicInbox/Search.pm b/lib/PublicInbox/Search.pm
index 2c66e557..f0040500 100644
--- a/lib/PublicInbox/Search.pm
+++ b/lib/PublicInbox/Search.pm
@@ -23,7 +23,8 @@ use constant {
         # 3 - message-ID is compressed if it includes '%' (hack!)
         # 4 - change "Re: " normalization, avoid circular Reference ghosts
         # 5 - subject_path drops trailing '.'
-        SCHEMA_VERSION => 5,
+        # 6 - preserve References: order in document data
+        SCHEMA_VERSION => 6,
         QP_FLAGS => FLAG_PHRASE|FLAG_BOOLEAN|FLAG_LOVEHATE|FLAG_WILDCARD,
 };
 
@@ -49,9 +50,9 @@ my %all_pfx = (%bool_pfx_internal, %bool_pfx_external, %prob_prefix);
 sub xpfx { $all_pfx{$_[0]} }
 
 our %PFX2TERM_RMAP;
+my %meta_pfx = (mid => 1, thread => 1, path => 1, type => 1);
 while (my ($k, $v) = each %all_pfx) {
-        next if $prob_prefix{$k};
-        $PFX2TERM_RMAP{$v} = $k;
+        $PFX2TERM_RMAP{$v} = $k if $meta_pfx{$k};
 }
 
 my $mail_query = Search::Xapian::Query->new(xpfx('type') . 'mail');
@@ -129,8 +130,6 @@ sub add_message {
                 my $ts = Search::Xapian::sortable_serialise($smsg->ts);
                 $doc->add_value(PublicInbox::Search::TS, $ts);
 
-                $doc->set_data($smsg->to_doc_data);
-
                 my $tg = $self->term_generator;
 
                 $tg->set_document($doc);
@@ -176,9 +175,11 @@ sub add_message {
                 if ($was_ghost) {
                         $doc_id = $smsg->doc_id;
                         $self->link_message($smsg, 0);
+                        $doc->set_data($smsg->to_doc_data);
                         $db->replace_document($doc_id, $doc);
                 } else {
                         $self->link_message($smsg, 0);
+                        $doc->set_data($smsg->to_doc_data);
                         $doc_id = $db->add_document($doc);
                 }
         };
@@ -352,14 +353,14 @@ sub link_message_to_parents {
         my @refs = $refs ? ($refs =~ /<([^>]+)>/g) : ();
         my $irt = $mime->header_obj->header('In-Reply-To');
         if ($irt) {
-                if ($irt =~ /<([^>]+)>/) {
-                        $irt = $1;
-                }
+                $irt = mid_compressed(mid_clean($irt));
 
                 # maybe some crazies will try to make a circular reference:
                 if ($irt eq $mid) {
                         $irt = undef;
                 } else {
+                        # last References should be $irt
+                        # we will de-dupe later
                         push @refs, $irt;
                 }
         }
@@ -376,12 +377,10 @@ sub link_message_to_parents {
                         $uniq{$ref} = 1;
                         push @refs, $ref;
                 }
-                $irt = undef if (defined $irt && !$uniq{$irt});
         }
         if (@refs) {
-                if (defined $irt) {
-                        $doc->add_term(xpfx('inreplyto') . $irt);
-                }
+                $doc->add_term(xpfx('inreplyto') . $irt) if defined $irt;
+                $smsg->{references_sorted} = '<'.join('><', @refs).'>';
 
                 my $ref_pfx = xpfx('references');