Cyrus IMAP BINARY FETCH error handling

[alecpl]

When Cyrus can't decode a mail part body requested in BINARY FETCH command it will not return an error (NO response) as you'd expect. Therefore Roundcube does not fallback to non-binary FETCH.

However, it does not return BINARY item in the response either, so we should be able to detect the error.

C: A0008 UID FETCH 2 (BINARY.PEEK[2])
S: * 2 FETCH (UID 2)
S: A0008 OK Completed (0.000 sec)

Reference: cyrusimap/cyrus-imapd#4567

[alecpl]

Fixed.