[Extra] SPECIAL-USE MAY appear in LIST responses (was: Re: I-D Action: draft-ietf-extra-sieve-special-use-01.txt)

[Ned Freed <[e-mail]>]

> > Yes, according to RFC 6154 section 2 special use attributes MAY
> > appear in> non-extended LIST responses. There's an example of this in
> > section 5.1.>

> > However, the fact that this is a MAY makes it effectively useless
> > since you> can't tell the difference between a case where there are no
> > special use> attributes assigned and one where the server has simply elected not
> > to include> these attributes in its responses. And it's expected that the
> > overwhelming> majority of mailboxes won't have any special use assigned.

> MAY fricking shmay.

:)

> There are clients out there which flat out expect
> that you return the SPECIAL-USE for an unadorned LIST, and customers
> report your server as buggy if it doesn't do what their client expects.

Well, if that's the case, we have a problem independent of this Sieve
extension. Do we need to at least file an errata on this?

> > In fact I'd go so far to say that this is a design error. It's
> > one thing> to want to support existing implementations of special use
> > attributes, it's> another to be so permissive that a compliant implementation - one that> supports SPECIAL-USE but not LIST-EXTENDED - can have no way to
> > determine> what the special use mailboxes are actually present.

> I'm sure that RFC3501bis (IMAP4rev2) will fix this.

Which creates a dependency on yet another IMAP extension. Not sure if
this is sufficient.

				Ned