[Dovecot] Issues with VANISHED CHANGEDSINCE

[Timo Sirainen]

On Mon, 2012-11-05 at 12:43 -0700, Michael M Slusarz wrote:
> My argument is much simpler: it is blatantly breaking the RFC.  From  
> RFC 5162 [3.2]:
> 
>     The VANISHED UID FETCH modifier instructs the server to report those
>     messages from the UID set parameter that have been expunged and whose
>     associated mod-sequence is larger than the specified mod-sequence.
>     **That is, the client requests to be informed of messages from the
>     specified set that were expunged since the specified  
> mod-sequence.** (emphasis added)
> 
> If you are including UIDs in the FETCH return that have NOT been  
> expunged since the given mod-sequence, that directly contradicts this  
> language.  The clear intent of VANISHED UID FETCH is to provide the  
> list of messages that existed in the mailbox at mod-sequence and no  
> longer exist in the mailbox as of the current HIGHESTMODSEQ.

That would require infinitely storing the modseq of when each message
was expunged. Not very nice. Also the RFC talks a lot about this
situation. The SELECT command has two optional parameters to optimize
it.