Add ui.strict config item. This turns off command matching by unambiguous prefix, and is a good thing if you want to write future-proof scripts. This fixes issue 314.

#!/bin/sh

hg init a
echo a > a/a
hg --cwd a ci -A -m a
hg clone a b
echo b > b/b
hg --cwd b ci -A -m b
chmod 100 a/.hg
hg --cwd b push ../a
chmod 700 a/.hg