imap: fix UID-offset-to-MSN mapping bugs

We need to clear the UID-offset-to-MSN mapping when
leaving mailboxes via EXAMINE/SELECT/CLOSE.

Furthermore, uo2m_last_uid() needs to account for tiny mailboxes
where the scalar representation of {uo2m} may be evaluated to
`false' in a boolean context.

diff --git a/lib/PublicInbox/IMAP.pm b/lib/PublicInbox/IMAP.pm
index 64b57a3ef69ada62d5cfbf6b57986d7fbc22d017..d8b1fce109ea151bdda1a6438d7d2f75219c332c 100644 (file)
--- a/lib/PublicInbox/IMAP.pm
+++ b/lib/PublicInbox/IMAP.pm
@@ -166,7 +166,7 @@ sub cmd_login ($$$$) {
 
 sub cmd_close ($$) {
        my ($self, $tag) = @_;
-       delete $self->{uid_base};
+       delete @$self{qw(uid_base uo2m)};
        delete $self->{ibx} ? "$tag OK Close done\r\n"
                                : "$tag BAD No mailbox\r\n";
 }
@@ -220,7 +220,7 @@ sub uo2m_hibernate ($) {
 
 sub uo2m_last_uid ($) {
        my ($self) = @_;
-       my $uo2m = $self->{uo2m} or die 'BUG: uo2m_last_uid w/o {uo2m}';
+       defined(my $uo2m = $self->{uo2m}) or die 'BUG: uo2m_last_uid w/o {uo2m}';
        (ref($uo2m) ? @$uo2m : (length($uo2m) >> 1)) + $self->{uid_base};
 }
 
@@ -415,6 +415,7 @@ sub cmd_examine ($$$) {
        my ($ibx, $exists, $uidnext, $base) = inbox_lookup($self, $mailbox);
        return "$tag NO Mailbox doesn't exist: $mailbox\r\n" if !$ibx;
        $self->{uid_base} = $base;
+       delete $self->{uo2m};
 
        # XXX: do we need this? RFC 5162/7162
        my $ret = $self->{ibx} ? "* OK [CLOSED] previous closed\r\n" : '';