dovecot - Aug 2005 - Dovecot IDLE problem (was Re: inotify support in dovecot)

Hi,

I've come across some possibly buggy behaviour with regards to Dovecot and
the
use of the IDLE keyword.  Found this while testing out inotify support for 
Johannes - although after asking him and him reproducing it, he is of the 
opinion that it's not a inotify specific problem.

The behaviour is that when the client is idling, Dovecot seems to only alert 
to the first new message received, and if a subsequent new message comes in 
before the client finishes idling, that second new message is not notified to 
the connected client.

To reproduce:

$ maildirmake /tmp/imap-test
$ cat >/tmp/1 <<EOF
From: test
To: test
Subject: test

test!
<Ctrl-D>
$ MAIL=Maildir:/tmp/imap-test /usr/libexec/dovecot/imap
...
A SELECT INBOX
B IDLE

[now, in a different terminal, copy /tmp/1 to /tmp/imap-test/new, you
should instantly be notified of it in your imap session]

** Dovecot correctly responds with:

* 1 EXISTS
* 1 RECENT

[if a second message is delivered, eg by copying /tmp/1 to 
/tmp/imap-test/new/2 then you should be notified as well, but this never occurs]

DONE
C LOGOUT
$

Timo - what do you think?

Reuben

--On Thursday, August 18, 2005 10:47 PM +1200 Reuben Farrelly 
<reuben-dovecot at reub.net> wrote:
> [if a second message is delivered, eg by copying /tmp/1 to
> /tmp/imap-test/new/2 then you should be notified as well, but this never
> occurs]
Is that true? I would think you only want notification one time after each 
new command (eg. IDLE), to indicate that the client is out-of-date wrt the 
server. It's essentially a "cache dirty" notification. It's
then the
client's job to bring itself up to date with the server state, at which 
point a new notification is appropriate.

BTW, does IMAP provide any notification ability for folders other than 
INBOX? I deliver via procmail to other folders and I believe Mulberry has 
to poll them periodically to check for new mail. (Different mailing lists 
and different friends each get their own folder.) Doing my filtering 
server-side means I don't need to maintain parallel filters on all my 
clients, on all the systems I use. (I gotta get around to doing the same 
for my address book, setting up an LDAP server.)

On Thu, 2005-08-18 at 22:47 +1200, Reuben Farrelly
wrote:
> The behaviour is that when the client is idling, Dovecot seems to only
alert
> to the first new message received, and if a subsequent new message comes in
> before the client finishes idling, that second new message is not notified
to
> the connected client.
It is notified, just not immediately. And it's intended to work like
that. If Dovecot tells the client about a new message and it doesn't
care enough about it enough to break IDLE, it doesn't need to know about
the second message immediately either.

Although I suppose with clients that use a second connection to read the
new mails this kind of behavior isn't exactly wanted.. Well, I'd like to
know if such clients exist before changing this.
> * 1 EXISTS
> * 1 RECENT
> 
> [if a second message is delivered, eg by copying /tmp/1 to 
> /tmp/imap-test/new/2 then you should be notified as well, but this never
occurs]
It should occur in 30-60sec or so.

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