mercurial/node.py

keyword: support mq; handle (q)record more gracefully

mq:
Ensure that expanded keywords do not make it into patches.
- disable expansion when reading filelog
- shrink expanded keywords when reading from working dir (wread)

(q)record:
Avoid additional hunks due to expanded keywords. However this is
still a compromise, as keyword expansions are not updated in
working directory because record should not overwrite files.

Mention above shortcomings and "hg kwexpand" workaround in help
and update test output.

system argument parsing:
Command detection might be slightly more expensive with
dispatch._parse, but we will need this for improving "hg diff"
output.

"""
node.py - basic nodeid manipulation for mercurial

Copyright 2005, 2006 Matt Mackall <[e-mail]>

This software may be used and distributed according to the terms
of the GNU General Public License, incorporated herein by reference.
"""

import binascii

nullrev = -1
nullid = "\0" * 20

# This ugly style has a noticeable effect in manifest parsing
hex = binascii.hexlify
bin = binascii.unhexlify

def short(node):
    return hex(node[:6])