The purpose of
`if version and not gajim.contacts.get_contacts_jid_list()`
seemed to be that when cache.db is empty (maybe it was deleted)
`gajim.contacts.get_contacts_jid_list()` should come back empty.
So on an empty roster cache, version was set to None, so that we
request in any case a new roster.
The Problem is that `gajim.contacts.get_contacts_jid_list()` is not
a good indication for an empty cache.db. On start we trigger a
`RosterReceivedEvent` which does a DB query to get the roster. Even
if that DB query comes up empty, the Event is still pushed.
In the event handler `_nec_roster_received` in roster_window.py we
add then previously open controls and our self (if the option is set)
to the roster, making `gajim.contacts.get_contacts_jid_list()` return
these contacts and hence the condition in `request_roster()` always
False.
So the version is set in the roster request, and if there is no new
version on the server, we request no new roster even though we only
have ourself and previously open controls in our roster.
As a solution for this we delete the roster version from the config
in `RosterReceivedEvent` if the DB query comes back empty, which
triggers a new roster request.
muc_restore_timeout set to -1 means we want no particular time set, up
to which we request messages. But we should not deliberate request
messages we already have. Hence even if muc_restore_timeout is set
to -1, we should only request up to the last message we received.
Example:
If we receive a message the last message date is now.
If we restart Gajim and join the MUC again, `time.time() - timeout`
will be most likly smaller then when we received the last message
If the timeout is an hour, this would mean that many messages are requested
from the archive which we already received.
So we always want the most current timestamp (MAX).
Philipp Hörist
André Apitzsch