# hgdemandimport - global demand-loading of modules for Mercurial

#

# Copyright 2017 Facebook Inc.

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

'''demandimport - automatic demand-loading of modules'''

# This is in a separate package from mercurial because in Python 3,

# demand loading is per-package. Keeping demandimport in the mercurial package

# would disable demand loading for any modules in mercurial.

import os

import sys

from . import demandimportpy3 as demandimport

# Full module names which can't be lazy imported.

# Extensions can add to this set.

IGNORES = {

    '__future__',

    '_hashlib',

    # ImportError during pkg_resources/__init__.py:fixup_namespace_package

    '_imp',

    '_xmlplus',

    'fcntl',

    'nt',  # pathlib2 tests the existence of built-in 'nt' module

    'win32com.gen_py',

    'win32com.shell',  # 'appdirs' tries to import win32com.shell

    '_winreg',  # 2.7 mimetypes needs immediate ImportError

    'pythoncom',

    # imported by tarfile, not available under Windows

    'pwd',

    'grp',

    # imported by profile, itself imported by hotshot.stats,

    # not available under Windows

    'resource',

    # this trips up many extension authors

    'gtk',

    # setuptools' pkg_resources.py expects "from __main__ import x" to

    # raise ImportError if x not defined

    '__main__',

    '_ast',  # https://bugs.python.org/issue41631

    '_ssl',  # conditional imports in the stdlib, issue1964

    '_sre',  # issue4920

    'rfc822',

    'mimetools',

    'sqlalchemy.events',  # has import-time side effects (issue5085)

    'sqlalchemy.dialects',  # similar problems as above

    # setuptools 8 expects this module to explode early when not on windows

    'distutils.msvc9compiler',

    '__builtin__',

    'builtins',

    'urwid.command_map',  # for pudb

    'lzma',

}

_pypy = '__pypy__' in sys.builtin_module_names

if _pypy:

    # _ctypes.pointer is shadowed by "from ... import pointer" (PyPy 5)

    IGNORES.add('_ctypes.pointer')

    # pure Python module on PyPy, must be loaded to raise ModuleNotFoundError

    # on non-Windows platforms

    IGNORES.add('msvcrt')

demandimport.init(IGNORES)

# Re-export.

isenabled = demandimport.isenabled

disable = demandimport.disable

deactivated = demandimport.deactivated

def enable():

    # chg pre-imports modules so do not enable demandimport for it

    if (

        'CHGINTERNALMARK' not in os.environ

        and os.environ.get('HGDEMANDIMPORT') != 'disable'

    ):

        demandimport.enable()