index: don't include nullid in len()
I suspect the reason the nullid is in the index in the last position
is that it lets index[i] for regular revision number, even when index
was just a regular Python list. An alternative solution would have
been to reserve revision number 0 for the null revision. I don't know
why that wasn't done. Now that we have classes backing the index, we
can easily make index[-1] get the nullid without having to put it last
in the list and including it in the len().
This patch just hides the nullid -- it will still be accessible at
index[len(index)].
I realize that this will be annoying when checking out across this
commit for debugging (including bisection).
Differential Revision: https://phab.mercurial-scm.org/D4022
#!/bin/sh
# This scripts is used to setup temp directory in memory
# for running Mercurial tests in vritual machine managed
# by Vagrant (see Vagrantfile for details).
cd /hgshared
make local
cd tests
mkdir /tmp/ram
sudo mount -t tmpfs -o size=100M tmpfs /tmp/ram
export TMPDIR=/tmp/ram
./run-tests.py -l --time