Re: [Evolution] Evolution lost my follow-up flags after an IMAP server update

[Milan Crha <mcrha redhat com>]

On Mon, 2017-05-29 at 13:30 -0300, Jorge Morais Neto wrote:
> On 29 May 2017 at 12:13, Jorge Morais Neto <jorge13515 gmail com>
> wrote:
> > [...] Two problems remained in Evolution:
> > 1. In one large folder, all emails became unread.
> > 2. I lost all follow-up flags.
> >
> > I am not concerned about problem 1, but I would like a solution for
> > problem 2.  Do you have ideas?
>
> I forgot to mention: some messages in many folders are still marked
> Important, so it seems I have not lost the Important flag.  The same
> holds for the (color-coded) labels.

        Hi,
I briefly looked into the source code and it looks like the follow-up
tags are stored only locally when using IMAP. The labels and other
flags are stored on the server (if the server supports it, which seems
like your sever does support it).

I suppose that the server changed uid-validity for the folders, which
means that the UID-s as they had been advertised previously do not
match (may not match), thus the client is asked to clean up its local
cache re-fetch everything from scratch. As there is no reliable
matching between the local (now invalidated by the server) UID-s and
the newly advertised UID-s, the IMAPx code did not "upgrade" the
message tags and basically lost them. Trying to recover them from a
backup (if any) of the local folders.db file for this account would be
quite complicated. The hardest to match the message in the folders.
Maybe when the Message-ID header from the actual message could be used,
then it'll work.

Interestingly, I didn't find any request to store message tags (like
the Follow-up) on the server for IMAP accounts in GNOME bugzilla. I
would expect there is something for it (I do not mean by you, I mean a
general request). There would be a problem with interoperability with
other clients, and I'm not sure whether custom user flags are the right
place to store it on the server, but maybe not a big problem.
        Bye,
        Milan