mercurial/policy.py

tests: correct (I think) command in test-largefiles-update

When this test was introduced, it used the short-form of all the flags
on this update invocation. I suspect, based on the "start with clean
dirstates" comment and the fact that the no-exec branch of the #if
guard leaves dirstate clean, that this should have been 'update -qCr'
instead of 'update -qcr', but that a bug in largefiles --check
handling left this problem unnoticed.

I'll leave a breadcrumb further up about the current failure mode in
the hopes that we can fix this some day.

This was previously discussed in [0] but the trail in that thread goes
cold after a few replies. Given that this is still a flaky test, that
appears to only be passing by bad fortune, I think it's worth
correcting the code of the test to make a correct assertion, and to
keep track of the suspected bug with some other mechanism than an
invalid test (if we had support for "expected failure" blocks this
might be a worthwhile use of them?).

0: https://www.mercurial-scm.org/pipermail/mercurial-devel/2016-October/089501.html

# policy.py - module policy logic for Mercurial.
#
# Copyright 2015 Gregory Szorc <[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 os
import sys

# Rules for how modules can be loaded. Values are:
#
#    c - require C extensions
#    allow - allow pure Python implementation when C loading fails
#    cffi - required cffi versions (implemented within pure module)
#    cffi-allow - allow pure Python implementation if cffi version is missing
#    py - only load pure Python modules
#
# By default, require the C extensions for performance reasons.
policy = 'c'
policynoc = ('cffi', 'cffi-allow', 'py')
policynocffi = ('c', 'py')

try:
    from . import __modulepolicy__
    policy = __modulepolicy__.modulepolicy
except ImportError:
    pass

# PyPy doesn't load C extensions.
#
# The canonical way to do this is to test platform.python_implementation().
# But we don't import platform and don't bloat for it here.
if '__pypy__' in sys.builtin_module_names:
    policy = 'cffi'

# Our C extensions aren't yet compatible with Python 3. So use pure Python
# on Python 3 for now.
if sys.version_info[0] >= 3:
    policy = 'py'

# Environment variable can always force settings.
policy = os.environ.get('HGMODULEPOLICY', policy)