Re: offlineimap's handling of moving message

[John Goerzen <jgoerzen@xxxxxxxxxxxx>]

On Wednesday 26 December 2007 4:20:18 pm Joel Mawhorter wrote:
> Hi all,
>
> I'm trying to use offlineimap with Gmail and I'm running into a problem.
> If I move a message from folder A to folder B using my mail client (mutt),
> then next time I run offlineimap the message is deleted from folder A on
> the server and then uploaded to folder B on the server. For large messages
> this is too inefficient for my uses since the whole message gets sent to
> the remote server even though it is already there. Is there a way around
> this or is this an inherent limitation of having a client other than your
> mail client manage synchronization?

Not a reliable one.

OfflineIMAP would have to have a way to know that a new message that suddenly 
appeared in a new folder was originally a message with UID x in folder y, 
and that this message with UID x was still in folder y on the server -- 
which may not be the case if you had accessed your IMAP box by other means 
and deleted it.

IMAP does not have a MOVE command.  It does have a COPY, which OfflineIMAP 
does not use.

OfflineIMAP also operates on each folder individually.  It would be possible 
to make it detect and use COPY in this situation, but would be a fairly 
significant code change.  Consider: what if you moved a message from folder 
A to folder B, and also a message from folder B to folder A?  You would have 
to scan all folders for changes before you started processing any at all, 
lest you delete on the server the source for a COPY.

In short, I think that this optimization adds quite a bit of complexity for 
relatively little gain.

-- John