Questions about SPECIAL-USE IMAP extension

[Tanstaafl]

On Wed Jan 17 2018 15:56:39 GMT-0500 (Eastern Standard Time), Joseph Tam
<jtam.home at gmail.com> wrote:
> Thanks.  How does this manifests itself: the client gets an inconsistent
> view of the outgoing mailbox that depends on which mailbox the client
> is using, or the optimization is broken and dovecot keeps having to
> (re)read the mailbox to acquire the IMAP STATUS?

The way I think this should work is simple...

If the Client doesn't request one of the pre-defined 'aliases' for a
special use folder, then it simply does what it does now - uses what it
wants (creates it if it doesn't exist).

As far as I can tell, this would require dovecot to add some 'smarts'
with respect to virtual folders, and be able to create these on the fly
for clients, as virtual folders is how I think these special-use aliases
should be presented to the client, unless someone has a better idea.

So, for example, if a client asks for a special use folder that did not
use to be pre-defined (Admin added it sometime after the client
connected before), it moves any emails currently residing in the real
version of what will be the new 'alias' (virtual) folder to the alias
target (the real special use folder on the filesystem), deletes the real
version, then creates and subscribes to the new virtual folder.

As I said, properly coded, this could be painless and mostly invisible
to the client.