topic: use more protective code to access current topic
There are some code path where the operation is not properly initialized and
lack the new attributes. While the lack of initialization, is suspicious and
I've not be able to pin point case where this happens.
Currently the code crash when it encounter this situation. So we make the code
more resistant to this case to prevent bad user experience.
This software was downloaded from
https://www.mercurial-scm.org/repo/evolve/
Copyright 2011 Peter Arrenbrecht <peter.arrenbrecht@gmail.com>
Logilab SA <contact@logilab.fr>
Pierre-Yves David <pierre-yves.david@ens-lyon.org>
Patrick Mezard <patrick@mezard.eu>
This software may be used and distributed according to the terms of the GNU
General Public License version 2 or any later version.
On Debian systems, the complete text of the GNU General Public License version
2 can be found in `/usr/share/common-licenses/GPL-2'.