setup: display return code information about failed `hg` call
This help to understand what is going wrong when things goes wrong.
from mercurial.i18n import _
from mercurial import changegroup, error, extensions
def abort(orig, *args, **kwargs):
raise error.Abort(_('this is an exercise'))
def uisetup(ui):
extensions.wrapfunction(changegroup, 'getbundler', abort)