Re: [Evolution] Mails moved to another folder by filter also end up in trash folder

[Pete Biggs <pete biggs org uk>]

On Sun, 2015-02-22 at 10:22 -0500, Dennis Reichel wrote:
> With Evolution 3.12.10 (as well as all previous versions I'm aware of),
> when email is moved to another folder, be it by filter rule or manually
> a duplicate message appears in Trash.  

The short memories of the internet ...

IMAP, until very recently, didn't have the concept of a "MOVE".  A move
operation is implemented as a "COPY" + "DELETE".  Hence the fact that a
message appears in the Trash.  In fact "Trash" is also something that
IMAP didn't (doesn't?) know about - a message is marked as "DELETED"
only, and stays in the folder.  The best way of seeing this is to turn
off the "hide deleted messages" (or turn on the "show deleted messages"
depending on your version).  You will then be able to see what is
happening.  The Trash folder on Evolution is a virtual folder showing
the messages that are marked as deleted in all the folders of the
account. (Unless you've changed the defaults for the account)

This has been gone over many times on this mailing list over the last 12
years I've been on it!

> I believe this is only the case with IMAP mail accounts.  Trying to
> confirm this, I copied several messages to folders "On this computer"
> and moved them about without the messages appearing in Trash.

It used to be that even internally to Evo a move was implemented as copy
+delete.  But that appears to have changed recently (I don't use local
folders).

Even for IMAP, Evo will now use the MOVE command if the server supports
it (which confused me immensely the first time it happened - I *liked*
the copy+delete.

> This inconsistent behavior suggests that the messages going to Trash are
> an artifact of interaction with the remote server via IMAP more so than
> an intentional feature.
>
> Negative effects of this cloning into trash include:

It is NOT cloned into trash.  The message is marked as deleted in the
original folder and what you are seeing is a virtual folder containing
references to the deleted messages.  No messages are "moved" to the
trash in the process.

> 1) The end user, when auditing the contents of Trash prior to expunging
> may be compelled to confirm that some important and/or unread emails
> also reside in another location in the message store.

Make deleted messages visible, it makes things a lot clearer!

> 2) This increases the footprint and processing overhead of the message
> store, while adding no discernible value.

Nope, doesn't change any "processing overhead".

> 3) It is inconsistent with the operation of POP3 mail accounts and
> somewhat disconcerting.

IMAP and POP3 are totally different things - I would say that POP3
processing is inconsistent with IMAP operation ...

Besides, the handling of internal Evolution mail stores (which is
effectively what POP3 is) used to use the IMAP model, but users,
apparently, didn't like it and didn't see any need for them to be
mutually consistent ...

> If it is technically impractical to alter Evolution so this does not
> occur, would it not be possible to flag or process these messages
> differently so that the end user or a mail filter can quickly and
> easily scan Trash and identify which mails reside there as a result
> of moving them to another folder?    

Make deleted messages visible and expunge (Ctrl-E) individual folders.

In the virtual trash folder add a "source" column - that will tell you
where each of the deleted messages actually resides.

Other than that the virtual Trash folder just displays messages marked
as "DELETED" - there is no distinction between messages deleted and
those deleted as a result of a copy+delete.

P.