cubicweb-vcsfile #4128928 crash on add_revision_hook (mercurial 3 related ?) [deprecated]

This occurs when using vcwiki cube upon creation of the first page. The (hg) repository is initialized but has no revision yet (just called hglib.init()).

Traceback (most recent call last):
  File "/home/dlaxalde/projects/sncf/grshell/cubicweb/web/application.py", line 467, in core_handle
    txuuid = req.cnx.commit()
  File "/home/dlaxalde/projects/sncf/grshell/cubicweb/dbapi.py", line 525, in decorator
    return func(self, *args, **kwargs)
  File "/home/dlaxalde/projects/sncf/grshell/cubicweb/dbapi.py", line 751, in commit
    return self._repo.commit(self.sessionid, **self._txid())
  File "/home/dlaxalde/projects/sncf/grshell/cubicweb/server/repository.py", line 852, in commit
    return session.commit()
  File "/home/dlaxalde/projects/sncf/grshell/cubicweb/server/session.py", line 1253, in commit
    operation.handle_event('precommit_event')
  File "/home/dlaxalde/projects/sncf/grshell/cubicweb/server/hook.py", line 765, in handle_event
    getattr(self, event)()
  File "/home/dlaxalde/projects/sncf/grshell/cubes/vcsfile/hooks.py", line 146, in precommit_event
    self.transaction.precommit()
  File "/home/dlaxalde/projects/sncf/grshell/cubes/vcsfile/repohg.py", line 523, in precommit
    self.hgparent = p1 = self.repo.branchmap().branchtip('default')
  File "/usr/lib/python2.7/dist-packages/mercurial/branchmap.py", line 186, in branchtip
    return self._branchtip(self[branch])[0]
KeyError: 'default'

Probably due to mercurial 3.

prioritynormal
typebug
done in<not specified>
load0.000
load left0.000
closed by<not specified>