lei: relax rules for "new" in Maildir

mbsync and offlineimap both use ":2," suffixes for filenames in
"new/", however my interpretation of the Maildir spec at
<https://cr.yp.to/proto/maildir.html> is that ":2," is only for
files in "cur/".  My interpretation also matches that of
doveecot, but we'll allow what mbsync and offlineimap do given
their popularity.

1 files changed, 10 insertions, 3 deletions

diff --git a/lib/PublicInbox/LeiMailSync.pm b/lib/PublicInbox/LeiMailSync.pm
index 803de48c..3bada42d 100644
--- a/lib/PublicInbox/LeiMailSync.pm
+++ b/lib/PublicInbox/LeiMailSync.pm
@@ -233,9 +233,16 @@ WHERE b.oidbin = ?
         $b2n->execute(pack('H*', $oidhex));
         while (my ($d, $n) = $b2n->fetchrow_array) {
                 substr($d, 0, length('maildir:')) = '';
-                my $f = "$d/" . ($n =~ /:2,[a-zA-Z]*\z/ ? "cur/$n" : "new/$n");
-                open my $fh, '<', $f or next;
-                if (-s $fh) {
+                # n.b. both mbsync and offlineimap use ":2," as a suffix
+                # in "new/", despite (from what I understand of reading
+                # <https://cr.yp.to/proto/maildir.html>), the ":2," only
+                # applies to files in "cur/".
+                my @try = $n =~ /:2,[a-zA-Z]+\z/ ? qw(cur new) : qw(new cur);
+                for my $x (@try) {
+                        my $f = "$d/$x/$n";
+                        open my $fh, '<', $f or next;
+                        # some (buggy) Maildir writers are non-atomic:
+                        next unless -s $fh;
                         local $/;
                         my $raw = <$fh>;
                         if ($vrfy && git_sha(1, \$raw)->hexdigest ne $oidhex) {