On Jul 03 2015, Greg Troxel <gdt@lexort.com> wrote:
> Nikolaus Rath <Nikolaus@rath.org> writes:
>
>> This patch introduces a new server variable, nnimap-hide-deleted. If
>> non-nil, articles with the IMAP \Deleted flag will not be included in
>> Summary buffers.
>>
>> This is intended to increase operability with other IMAP mailreaders and
>> the new 'never value for nnimap-expunge (see patch in bug 20670).
>
> I haven't reviewed the patch, but the functionality is needed.  I find
> that on deleting messages with GUI IMAP clients, they are still seen in
> gnus.
>
> I find the deletion notion in IMAP confusing, between move-to-trash and
> just-marked-deleted-but-keep, and don't really know how the articles end
> up in the trash folder using the just-mark scheme, but it hasn't
> bothered me enough to dig in.

It's really pretty simple. There is no concept of a trash folder in
IMAP. Deleting a message means marking it with the \Deleted flag. The UA
is expected to take that into account when showing the mailbox contents
(e.g. by hiding such messsages or showing them crossed out). A message
can be physically deleted by "expunging" it (that would correspond to
emptying the trash).

Any trash folder in an IMAP mailbox is a totally ordinary folder, and if
there are messages in it it means that they have been moved there (i.e.,
not deleted). To empty the trash, you still have to mark the message as
\Deleted, *and* then expunge it.



Best,
-Nikolaus

-- 
GPG encrypted emails preferred. Key id: 0xD113FCAC3C4E599F
Fingerprint: ED31 791B 2C5C 1613 AF38 8B8A D113 FCAC 3C4E 599F

             »Time flies like an arrow, fruit flies like a Banana.«