-sub uniq_mids {
- my ($hdr, @fields) = @_;
- my %seen;
- my @raw;
- foreach my $f (@fields) {
- push @raw, $hdr->header_raw($f);
+# we allow searching on X-Alt-Message-ID since PublicInbox::NNTP uses them
+# to placate some clients, and we want to ensure NNTP-only clients can
+# import and index without relying on HTTP endpoints
+sub mids_for_index ($) {
+ mids_in($_[0], qw(Message-ID X-Alt-Message-ID));
+}
+
+# last References should be IRT, but some mail clients do things
+# out of order, so trust IRT over References iff IRT exists
+sub references ($) {
+ my ($hdr) = @_;
+ my @mids;
+ foreach my $f (qw(References In-Reply-To)) {
+ my @v = $hdr->header_raw($f);
+ foreach my $v (@v) {
+ push(@mids, ($v =~ /$MID_EXTRACT/g));
+ }
+ }
+
+ # old versions of git-send-email would prompt users for
+ # In-Reply-To and users' muscle memory would use 'y' or 'n'
+ # as responses:
+ my %addr = ( y => 1, n => 1 );
+
+ foreach my $f (qw(To From Cc)) {
+ my @v = $hdr->header_raw($f);
+ foreach my $v (@v) {
+ $addr{$_} = 1 for (PublicInbox::Address::emails($v));
+ }