MBOX-Line: From dkarp at zimbra.com  Tue Mar 20 13:42:17 2012
To: imap-protocol@u.washington.edu
From: Dan Karp <dkarp@zimbra.com>
Date: Fri Jun  8 12:34:48 2018
Subject: [Imap-protocol] CONDSTORE mod-sequence values
In-Reply-To: <CABHfyPSq=7hOtH94aet6T=osoXmfVP94iAq6iCCYH3N+MvGmFw@mail.gmail.com>
Message-ID: <1370186682.140190.1332276137465.JavaMail.root@zimbra.com>

> From RFC4551 Introduction: "The server MUST guarantee that each STORE
> command performed on the same mailbox ... will get a different
> mod-sequence value."
> 
> Can someone explain why the uniqueness requirement is necessary for
> the modification sequence? If two metadata items/messages are
> modified transactionally and share the same mod-sequence I don't
> really see any way that will break any of the proposed IMAP protocol
> changes for CONDSTORE (as long as they are updated atomically and a
> client can't sync between when a first item gets a mod-sequence and
> a second item gets the same mod-sequence).

I *think* that you're incorrectly interpreting "each STORE command" as
"each message affected by a STORE command".  The following command is
one STORE command, not ten:

   A001 STORE 1:10 +FLAGS (\Deleted)

Your single transactional modification of those ten messages is allowed
to use the same mod-sequence value.

- Dan

