mercurial/node.py

testing: allow Hypothesis tests to disable extensions

Doing this required the introduction of a mechanism for keeping
track of more general config in the test. At present this is only
used for extensions but it could be used more widely (e.g. to
control specific extension behaviour)

This greatly simplifies the extension management logic by introducing
a general notion of config, which we maintain ourselves and pass to
HG on every invocation.

This results in significantly less error prone test generation, and
also allows us to turn extensions off as well as on.

The logic that used an environment variable to rerun the tests with
an extension disabled now just edits the test file (in a fresh copy)
to remove these --config command line flags.

# 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 version 2 or any later version.

from __future__ import absolute_import

import binascii

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

nullrev = -1
nullid = "\0" * 20
nullhex = hex(nullid)

# pseudo identifiers for working directory
# (they are experimental, so don't add too many dependencies on them)
wdirrev = 0x7fffffff
wdirid = "\xff" * 20

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