Re: [Evolution] sync error for tasks

[Milan Crha <mcrha redhat com>]

On Wed, 2019-09-18 at 12:56 +0200, Anirudh Nihalani Vattikonda wrote:
> The task list backend servicing “Personal” encountered an error.
>
> The reported error was “Failed to delete resource: HTTP error code
> 412 (Precondition failed): Sabre\DAV\Exception\PreconditionFailed
>   An If-Match header was specified and the resource did not exist
>   If-Match[exception][message][header]”.
>
> Calendar is working fine though it's just the tasks that throw this
> error. Any suggestions on how to fix this?

        Hi,
it seems to me that the local cache contains a task, which is not part
of the server anymore, but it is "recorded" to be deleted and the code
cannot get rid of it (possibly due to unexpected error code being
returned by the server [1]).

You can workaround that by cleaning up the local cache and letting the
task list to re-download the content from the server from scratch.

The usual place for these tasks is 

   ~/.cache/evolution/tasks/<task-list-id>/

but as you seem to be using 3.34.0 from Flathub; it's stored in

   ~/.var/app/org.gnome.Evolution/cache/evolution/tasks/<task-list-id>/

instead.

You should not touch those files when the evolution-data-server
background processes are running, especially the evolution-calendar-
factory process, but it's not that easy in some desktop environments,
thus the worst case would be to cleanup the local cache and then make
sure all `ps ax | grep evolution` processes are killed, where the
desktop environment can eventually restart some of them. The `evolution
--force-shutdown` in useful in these cases, but the Flatpak version
works differently. Maybe try:

   $ flatpak run --cmd "evolution --force-shutdown" org.gnome.Evolution

but no promises it'll work. The manual killing of the processes would
help. Those from Flatpak are in /app path in the `ps` command I gave
above. Or restart the machine after cleaning up the local cache.

As always, better to move the files away and delete them only after
you'll see the application works properly. This way you'll have
something to return to, in case anything would go wrong due to the
internal file changes you'd do.

        Bye,
        Milan

[1] https://gitlab.gnome.org/GNOME/evolution-data-server/issues/44