[Dovecot] Problem/workaround with X-Keywords and Apple's Mail.app

[Joey Coleman]

Hello,

   I've just switched from UW-IMAP to Dovecot, and for the most part,  
things are good.

   However, I encountered the problem with the X-Keywords header not  
being written back into individual messages in an mbox file  
(originally described in [1], and Timo gave a clue as to maybe why in  
[2]).

   What was happening for me is that Apple's Mail.app would flag a  
message as spam, which happily sets a couple keywords in the message,  
but those weren't being written back (at least, I didn't see them in  
the file on the server).  The "DO NOT DELETE..." message had a  
perfectly fine X-IMAP header, and up until I switched things were  
working great.

   The user visible symptom of this happened every time new spam  
arrived in my Junk folder [3] --- the new spam would arrive, be  
flagged as spam by Mail.app, and the earlier pieces of mail would  
promptly be unflagged!

   Anyway, Timo's clue in [2] prompted me to turn off both  
mbox_lazy_writes and mbox_dirty_syncs (the latter just on the off- 
chance... it's a low-volume server, so I can deal with the  
inefficiency).  Lo and behold, Mail.app started acting sane again  
*and* the X-Keywords header appeared immediately.

   Oddly, during all of this, the Status and X-UID keywords would  
appear in the messages just fine; no clue as to why those and not X- 
Keywords.

   Version details are:
     - Dovecot 1.0rc13 [4]
     - FreeBSD 5.3-RELEASE
     - Apple Mail.app 2.1 (752/752.2)

cheers,
--joey

[1] http://dovecot.org/list/dovecot/2006-March/011872.html
[2] http://dovecot.org/list/dovecot/2006-June/014126.html
[3] And it felt really strange while troubleshooting this as I found  
myself *hoping* for another piece of spam to arrive.  Bleh.
[4] Yes, two versions behind current, but in my defense, I did check  
the announcements and they didn't seem to mention the problem.