Re: [Evolution] Ordering of folders when filtering

[Milan Crha <mcrha redhat com>]

On Wed, 2016-05-11 at 10:38 +0200, Paul wrote:
> I do a bit of programming so I understand logic. What is the logic of
> these filters regarding folder order and messages already
> moved/copied?

        Hi,
filters are run in the order you see them in the Edit->Message Filters
dialog. The next filter is run unless the previous filter has an action
"Stop processing".

With respect of moved messages, it's much harder. I'm not verifying
this myself, thus this is only an opinion, but I think the filters
always run on the source folder and the message move doesn't change the
source folder to the new folder. Neither does message copy.

A usual practice is to do whatever changes you'd like to do on the
message and copy/move it to the right folder as the last action on the
message in that filter rule. For example, if you move the message
first, then set a label on it, then the message in the destination
folder will not have set the label, because you are still working with
the source message.

Some accounts can invoke a "message added" notification for the
messages which are added to the folder by the filters, in which case
the filters can be re-run on this new folder with this "new" message.
The IMAP account used to rely on the \Recent flag on the messages to
consider them for filtering, but it's not used for quite some time now,
because the \Recent flag is unreliable in a multi-client environment,
which is quite common these days, when people have running multiple
clients at the same time, checking the same IMAP account.

> If it is processed, how can one be sure the filter will process
> folder x first and not z (in which case the message will be only seen
> by the filter once)

By the order in the Message Filters dialog, with a help of the "Stop
Processing" action.

        Hope it helps,
        Milan