Don't modify the state when receiving an unsolicited FETCH response without UID

We require QRESYNC support (RFC 7162) for syncing, which requires UID
(MODSEQ) in unsolicited FETCH responses, cf RFC 7162 section 3.2.4.

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/Net/IMAP/InterIMAP.pm b/lib/Net/IMAP/InterIMAP.pm
index e3285de..0405794 100644
--- a/lib/Net/IMAP/InterIMAP.pm
+++ b/lib/Net/IMAP/InterIMAP.pm
@@ -2212,16 +2212,18 @@ sub _resp($$;$$$) {
                 undef $first;
             }
 
-            my $uid = $mail{UID} // $self->panic(); # sanity check
             $self->panic() unless defined $mail{MODSEQ} or !$self->_enabled('QRESYNC'); # sanity check
+            my $uid = $mail{UID};
 
             if (!exists $mail{RFC822} and !exists $mail{ENVELOPE} and # ignore new mails
+                defined $uid and # /!\ ignore unsolicited FETCH responses without UID, cf RFC 7162 section 3.2.4
                 (!exists $self->{_MODIFIED}->{$uid} or $self->{_MODIFIED}->{$uid}->[0] < $mail{MODSEQ} or
                     ($self->{_MODIFIED}->{$uid}->[0] == $mail{MODSEQ} and !defined $self->{_MODIFIED}->{$uid}->[1]))) {
                 my $flags = join ' ', sort(grep {lc $_ ne '\recent'} @{$mail{FLAGS}}) if defined $mail{FLAGS};
                 $self->{_MODIFIED}->{$uid} = [ $mail{MODSEQ}, $flags ];
             }
-            $callback->(\%mail) if defined $callback and ($cmd eq 'FETCH' or $cmd eq 'STORE') and in_set($uid, $set);
+            $callback->(\%mail) if defined $callback and ($cmd eq 'FETCH' or $cmd eq 'STORE') and
+                                   defined $uid and in_set($uid, $set);
         }
         elsif (/\AENABLED((?: $RE_ATOM_CHAR+)+)\z/) { # RFC 5161 ENABLE
             $self->{_ENABLED} //= [];