Mail client send token greater then 8K

[Vladimir Tyman]

Hello,

we encountered following problem:

We are using Cyrus on FreeBSD 4.8 stable and this versions (compiled
form ports):

cyrus-imapd-2.1.16_1 
cyrus-sasl-2.1.17_1
cyrus-sasl-saslauthd-2.1.17_1

and BDB downgraded from 4.1 to 4.0

and this returned "version" from cyradm CLI

mail.i.cz> ver
name       : Cyrus IMAPD
version    : v2.1.16 2003/11/19 16:45:28
vendor     : Project Cyrus
support-url: http://asg.web.cmu.edu/cyrus
os         : FreeBSD
os-version : 4.8-RELEASE-p13
environment: Cyrus SASL 2.1.17
              Sleepycat Software: Berkeley DB 4.0.14: (November 18, 2001)
              Built w/OpenSSL 0.9.7c 30 Sep 2003
              Running w/OpenSSL 0.9.7c 30 Sep 2003
              CMU Sieve 2.2
              TCP Wrappers
              mmap = shared
              lock = fcntl
              nonblock = fcntl
              auth = unix
              idle = poll
              mailboxes.db = skiplist
              seen.db = skiplist
              subs.db = flat
              deliver.db = db3-nosync
              tls_sessions.db = db3-nosync

User with client Linux Mozilla 1.4 (but M$ OE from IE 6 suite behaves
the same) moved cca. 3000 messages to Trash folder and when he tried 
to empty trash folder client does not display any new/recent message.

In imapd log are these errors:
...
Jan 29 11:56:14 ns imapd[48153]: Fatal error: word too long
...

Then we logged the next session of the user and relevant parts follow:

...
27 OK Completed
<1075371478<28 uid copy
28782,28784:28786,28788,28790:28795,28798,28807:28809,28
812,28816,28818:28819,28821:28822,28824,28827,28829:28830,28832:28833,28835:2883
7,28840:28842,28845:28847,28851:28854,28856:28858,28861:28862,28865,28868:28870,
28872:28873,28876:28882,28886,28888,28891:28894,28896,28898,28902:28903,28905:
...
33900,33902,33904,33910:33911,33915,33917,33920:33921,33923,33928:33931,33936,33
938,33940:33943,33945,33948:33951,33953:33954,33956,33959:33967,33969,33971,3397
3,33975:33990,33992:34002,34004:34006 "INBOX.MAIL-DELIVERY"
  >1075371478>* BYE Fatal error: word too long

In info-cyrus archive I found response from Ken Murchison related to question 
on the similar error:

  "Your client is sending either a token or quoted string that is longer
than 8K  bytes. In order to find out if this is a bug in the server or a
misbehaving  client, we need to see a protocol dump of a session which causes 
this error."

The token in dump is greater then 8K cca. 11K. Now I have the protocol dump
of the session to observe but I not sent it intentionally because its size 
(even compressed). I will send it of course on the request.
We would like to know if it is error in the Cyrus or in mail client.

There we have users which received thousands mails each day and
then it is easy to overrun the limit of token size when client operate
on set of all selected messages. 
Also it is hard to push users to make small selections.

Is somewhere (in IMAP's RFC) documented expected response or reaction 
of the client to this situation (fatal error for token oversize)?
Or how should idealy behave the mail client to this type of error 
from the IMAP server develepor point of view?
Is the client able from the error message recognise that it should 
shrink token to smaller size (not only specific to Cyrus imapd 
but generic)?

Regards

Vladimir Tyman
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