thread: sort incoming messages by Date

Improve the display by finding any parent when we see out-of-order
References.  This prevents us from having two roots in the test
case like Mail::Thread does.

2 files changed, 11 insertions, 4 deletions

diff --git a/lib/PublicInbox/SearchThread.pm b/lib/PublicInbox/SearchThread.pm
index 450a06f4..be290980 100644
--- a/lib/PublicInbox/SearchThread.pm
+++ b/lib/PublicInbox/SearchThread.pm
@@ -22,9 +22,16 @@ use strict;
 use warnings;
 
 sub thread {
-        my ($messages, $ordersub, $ibx) = @_;
+        my ($msgs, $ordersub, $ibx) = @_;
         my $id_table = {};
-        _add_message($id_table, $_) foreach @$messages;
+
+        # Sadly, we sort here anyways since the fill-in-the-blanks References:
+        # can be shakier if somebody used In-Reply-To with multiple, disparate
+        # messages.  So, take the client Date: into account since we can't
+        # alway determine ordering when somebody uses multiple In-Reply-To.
+        # We'll trust the client Date: header here instead of the Received:
+        # time since this is for display (and not retrieval)
+        _add_message($id_table, $_) for sort { $a->{ds} <=> $b->{ds} } @$msgs;
         my $rootset = [ grep {
                         !delete($_->{parent}) && $_->visible($ibx)
                 } values %$id_table ];
diff --git a/t/thread-cycle.t b/t/thread-cycle.t
index 9e915a12..78dcb6f9 100644
--- a/t/thread-cycle.t
+++ b/t/thread-cycle.t
@@ -85,13 +85,13 @@ SKIP: {
 }
 ($simples, $smsgs) = make_objs(reverse @backwards);
 my $forward = thread_to_s($smsgs);
-if ('Mail::Thread sorts by Date') {
+unless ('Mail::Thread sorts by Date') {
         SKIP: {
                 skip 'Mail::Thread missing', 1 unless $mt;
                 check_mt($forward, $simples, 'matches Mail::Thread forwards');
         }
 }
-unless ('sorting by Date') {
+if ('sorting by Date') {
         is("\n".$backward, "\n".$forward, 'forward and backward matches');
 }