Re: UID's, again, but with a twist :-)

[John Goerzen <jgoerzen@xxxxxxxxxxxx>]

On Mon, Mar 08, 2004 at 02:49:04PM +0100, Magnus Therning wrote:
> My first post after 'discovering' offlineIMAP in the latest issue of
> LinuxJournal :-)
> I have read both the manpage and the mail discussions on the UID
> problem. Now I am seeing some interesting behaviour in using mutt and
> offlineIMAP together:
> 
>  The validity of the UID for folders differs between runs!

First question: what IMAP server is in use on the server side?

This is almost always a server-side problem.  Here's an excerpt from the
offlineimap manpage:

       IMAP  servers  use  a  unique  ID (UID) to refer to a specific message.
       This number is guaranteed to be unique to a particular message forever.
       No  other  message in the same folder will ever get the same UID.  UIDs
       are an integral part of OfflineIMAP's synchronization scheme; they  are
       used to match up messages on your computer to messages on the server.

       Sometimes,  the  UIDs on the server might get reset.  Usually this will
       happen if you delete and then recreate a folder.   When  you  create  a
       folder,  the  server  will  often  start  the  UID  back  from  1.  But
       OfflineIMAP might still have the UIDs from the previous folder  by  the
       same  name stored.  OfflineIMAP will detect this condition and skip the
       folder.  This is GOOD, because it prevents data loss.

...

       Some  IMAP servers are broken and do not support UIDs properly.  If you
       continue to get this error for all your folders even  after  performing
       the above procedure, it is likely that your IMAP server falls into this
       category.   OfflineIMAP  is  incompatible  with  such  servers.   Using
       OfflineIMAP  with them will not destroy any mail, but at the same time,
       it will not actually synchronize it either.  (OfflineIMAP  will  detect
       this condition and abort prior to synchronization.)

       This  question  comes  up  frequently  on  the OfflineIMAP mailing list
       <URL:http://lists.complete.org/offlineimap@xxxxxxxxxxxx/>.    You   can
       find       a       detailed      discussion      <URL:http://lists.com-
       plete.org/offlineimap@xxxxxxxxxxxx/2003/04/msg00012.html.gz>   of   the
       problem there.

One other possibility is that something on the client side is destroying
OfflineIMAP's UID validity file -- but that is quite unlikely.

Take a look at the above and let me know what you think.

-- John