reverse sense of return value from python hooks.
old scheme (False/None/0/'' == fail) made coding style
unnatural, did not allow use of mercurial commands as hooks.
new scheme (False/None/0 == pass) is pythonic, does not require peculiar
"return True" at ends of hooks, allows hooks like this:
[hooks]
# update working dir after push into this repo
changegroup.update = python:mercurial.commands.update
#!/bin/sh
hg init
echo This is file a1 > a
hg add a
hg commit -m "commit #0" -d "1000000 0"
ls
echo This is file b1 > b
hg add b
hg commit -m "commit #1" -d "1000000 0"
hg co 0
# B should disappear
ls