contrib/vagrant/provision.sh

lock: include Linux pid namespace identifier in prefix

Previously, the lock only contains a hostname as an attempt to detect pid
namespace difference. However, that's not enough on modern Linux - a single
hostname could have different pid namespaces.

That means if people run hg inside different PID namespaces with a same UTS
namespae, the lock would be broken - an hg proccess in pid namespace A will
think the lock having a "random" pid in pid namespace B is "dead" and remove
it.

This patch solves the above issue by appending an PID namespace identifier of
the current process to the lock prefix ("hostname"). It depends on /proc
being mounted properly. But I don't think there is a better way to get pid
namespace identifier reliably.

#!/bin/sh
# This scripts is used to install dependencies for
# testing Mercurial. Mainly used by Vagrant (see
# Vagrantfile for details).

export DEBIAN_FRONTEND=noninteractive
apt-get update
apt-get install -y -q python-dev unzip
# run-tests.sh is added by Vagrantfile
chmod +x run-tests.sh