Recently-APPENDed messages not showing up as RECENT responses after NOOP

[John J Lee]

Hi

I'm trying to figure out why a Python spam-filtering program, SpamBayes, 
crashes for me when running in IMAP client spam-classification mode 
against a Cyrus IMAP server, version "Cyrus v2.3.7-fmsvn9188" (the server 
is one of the mail.messagingengine.com ones from fastmail.fm).

I should say upfront that I imagine it may well be that the fault is with 
SpamBayes.  TBH, the reason I'm posting here is that a). it's clear the 
SpamBayes issue will only get fixed if I do it myself, and b). I've little 
doubt that any fix I come up with without the help of an IMAP guru would 
be a pure hack, a server resource hog and not work for other people.

The problem occurs when SpamBayes (specifically, sb_imapfilter.py) tries 
to add an X-Spambayes-Classification header to emails it has classified, 
in order to record whether it thought the mail was spam or not.  It does 
that by creating a new message with the added header, then deleting the 
old message (if there's a better way, I'd be grateful to learn about it). 
As soon as SpamBayes creates the new message, it tries to find the new 
message's UID.  To do that, it first looks for a RECENT response.  If it 
doesn't have one it its buffer, it sends a NOOP command.  If that doesn't 
result in a RECENT response, it keeps polling, issuing NOOP commands up to 
100 times (it doesn't sleep() between each poll).  If that fails, it dies 
horribly :-/

So, two questions:

1. Is the algorithm above a sane one?  Maybe I should ask instead "is
    there a better one"?

2. Does this reveal a bug in the Cyrus implementation?  If not, might it
    be a useful extension of Cyrus IMAP to support this kind of usage?


Thanks in advance for any help


John