Greetings,

I'm new to the list.  I have encountered what I believe to be a bug in the 
return of HIGHESTMODSEQ when talking to a IMAP client.  HIGHESTMODSEQ does not 
appear to be incrementing when a new message arrives.  The exact steps I took 
are:

1) Create a new mail account
2) Send a mail to the account, check that you can receive the email.  Send a 
second mail to the account.
3) perform a SELECT on the mailbox from a new session.

PMLK4 SELECT INBOX
* FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
* OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)] Flags 
permitted.
* 2 EXISTS
* 1 RECENT
* OK [UNSEEN 1] First unseen.
* OK [UIDVALIDITY 1334074920] UIDs valid
* OK [UIDNEXT 3] Predicted next UID
* OK [HIGHESTMODSEQ 1] Highest
PMLK4 OK [READ-WRITE] Select completed.

4) Retrieve the mail.  Then perform another SELECT on the mailbox from yet 
another session.

LLEP4 SELECT INBOX
* FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
* OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)] Flags 
permitted.
* 2 EXISTS
* 0 RECENT
* OK [UNSEEN 1] First unseen.
* OK [UIDVALIDITY 1334074920] UIDs valid
* OK [UIDNEXT 3] Predicted next UID
* OK [HIGHESTMODSEQ 1] Highest
LLEP4 OK [READ-WRITE] Select completed.

5) Send another mail to the account, and check SELECT again.

FKDA4 SELECT INBOX
* FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
* OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)] Flags 
permitted.
* 3 EXISTS
* 1 RECENT
* OK [UNSEEN 1] First unseen.
* OK [UIDVALIDITY 1334074920] UIDs valid
* OK [UIDNEXT 4] Predicted next UID
* OK [HIGHESTMODSEQ 1] Highest
FKDA4 OK [READ-WRITE] Select completed.

It appears as if HIGHESTMODSEQ is not being updated.  I can get HIGHESTMODSEQ 
to start updating correctly if I send a "UID FETCH 1 MODSEQ" or similar 
command, which appears to enable MODSEQ tracking at the server (according to 
the comment around line 173 in file src/lib-index/mail-index-modseq.c), but 
until that command is sent, MODSEQ tracking is not enabled and hence 
HIGHESTMODSEQ is always going to return 1.

According to RFC4551, the combination of HIGHESTMODSEQ and UIDVALIDITY should 
be sufficient to determine if the metadata associated with the mailbox has 
changed, but in this case looking at only those two parameters does not yield 
sufficient information about changes in the mailbox.  The mail client I'm using 
relies on the combination of HIGHESTMODSEQ and UIDVALIDITY to determine if 
there are changes in the mailbox, and hence does not see new mail come in.

It seems that Dovecot should not be returning HIGHESTMODSEQ in response to a 
command if MODSEQ tracking is not enabled, but I could be wrong.  I've attached 
my configuration (it's Dovecot 2.0.18 running on Debian Stable).

Let me know if you need more information.

Glenn.

---------------------------------------------------------------------
This transmission (including any attachments) may contain confidential 
information, privileged material (including material protected by the 
solicitor-client or other applicable privileges), or constitute non-public 
information. Any use of this information by anyone other than the intended 
recipient is prohibited. If you have received this transmission in error, 
please immediately reply to the sender and delete this information from your 
system. Use, dissemination, distribution, or reproduction of this transmission 
by unintended recipients is not authorized and may be unlawful.

Attachment: dovecot.conf
Description: dovecot.conf

Reply via email to