Re: [Extra] I-D Action: draft-ietf-extra-imap4rev2-29.txt

[Alexey Melnikov <[e-mail]>]

On 15/02/2021 13:23, Timo Sirainen wrote:

> On 15. Feb 2021, at 14.16, Alexey Melnikov <[e-mail] 
> <mailto:[e-mail]>> wrote:
>>
>>> And I've a feeling that even seeing (\NonExistent \Trash) LIST reply 
>>> is going to confuse them.
>>
>> This is not really a new problem for IMAP4rev2. I suspect clients 
>> that want to support this, but don't at the moment, would need to be 
>> updated.
>>
>> I coded this in our client, because this is the only way to announce 
>> special use mailbox names, when the server doesn't support special 
>> use mailbox creation.
>
> I'm not sure what you mean by this. When server doesn't support 
> CREATE-SPECIAL-USE?
Yes.
> Dovecot only returns special-use for existing mailboxes. So you can 
> configure it to e.g. use Trash folder for \Trash, but LIST returns it 
> only when Trash actually exists.
In M-Box names are globally configured, so advertised automatically for 
all users.
> The more common configuration also sets the special-use folders to be 
> autocreated, so LIST always returns them as if they already exist.
Well, that is another way of doing the same thing.
> I'm not sure what benefit there would be for having a configuration 
> that returns them in LIST reply as \NonExistent, except for this kind 
> of a multi-namespace setup that is likely gone with the UW-IMAP server 
> (although Dovecot can be configured that way as well, but I don't see 
> why anyone would).

I don't think presence of multiple namespaces actually matters for this. 
I mean special use attributes are generic useful even if a single 
namespace exists.

Best Regard,

Alexey