view mercurial/policy.py @ 29486:a62c00f6dd04

sslutil: use certificates provided by certifi if available

The "certifi" Python package provides a distribution of the
Mozilla trusted CA certificates as a Python package. If it is
present, we assume the user intends it to be used and we use
it to provide the default CA certificates when certificates
are otherwise not configured.

It's worth noting that this behavior roughly matches the popular
"requests" package, which also attempts to use "certifi" if
present.

# 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
#    py - only load pure Python modules
#
# By default, require the C extensions for performance reasons.
policy = 'c'
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 = 'py'

# 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)