+sub ext_msg_i {
+ my ($other, $arg) = @_;
+ my ($cur, $mid, $ibxs, $found) = @$arg;
+
+ return if $other->{name} eq $cur->{name} || !$other->base_url;
+
+ my $mm = $other->mm or return;
+
+ # try to find the URL with Msgmap to avoid forking
+ my $num = $mm->num_for($mid);
+ if (defined $num) {
+ push @$found, $other;
+ } else {
+ # no point in trying the fork fallback if we
+ # know Xapian is up-to-date but missing the
+ # message in the current repo
+ push @$ibxs, $other;
+ }
+}
+