evolve: extract logic of pre-checking divergence risk to its own function
Extracting the logic (which is used to check if rewriting an obsolete
revision will create divergence) to a function. This function will be used
in upcoming patches of pre-checking.
This is how we check if rewriting an obsolete revision will create
divergence. We need to check two cases:
If there is any
1) non-obsolete successor.
-> easily done by `obsutil.successorssets()`
2) precursor with non-obsolete successor.
-> using `evolvecmd.divergentsets()`
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'.