view hgdemandimport/__init__.py @ 38573:050fbd9d103a

test-convert: demonstrate an unstable hash issue for bzr -> hg -> hg

It looks like the manifest value changing is the only difference, but I'm not
sure why it's happening.  I've got a similar divergence in a production repo
that was also converted from bzr and has an octopus merge[1].  Unlike here, the
manifest values for the destination merge commits reflect the initial merge
only, instead of all four merges agreeing like this test.

    $ hg -R src_repo manifest -r 310 --debug | grep file  # octopus fixup merge
    2d8775bc2481bd28ac87038ecdf33e1dbddc80e9 644   file1
    6adb9353a55bb8be76e71382efc724ec3ccf7ed5 644   file2

    $ hg -R src_repo manifest -r 309 --debug | grep file  # first merge
    362e7cb5163153c4989daad1a834871ae849f205 644   file1
    2c65d947191938c3ea616b7ceb7648ff3843261f 644   file2

    $ hg -R dst_repo manifest -r 273 --debug | grep file  # octopus fixup merge
    362e7cb5163153c4989daad1a834871ae849f205 644   file1
    2c65d947191938c3ea616b7ceb7648ff3843261f 644   file2

    $ hg -R dst_repo manifest -r 272 --debug | grep file  # first merge
    362e7cb5163153c4989daad1a834871ae849f205 644   file1
    2c65d947191938c3ea616b7ceb7648ff3843261f 644   file2

This divergence is espcially annoying because unlike changelog differences, I
haven't figured out a way to fix this in code.  The only way I found to work
around it is to convert up to the point of divergence, `hg bundle` the bad
revision in the source, apply it to the destination, add a line to the shamap,
and fire off the conversion again.

But I suspect that there's more to it than just the octopus merge because
I also have a commit in the same repo, done in Mercurial (well after the
conversion) that is exhibiting a similar issue (and it's not a merge commit).
I'm almost positive that it was created with 4.4 or later.  Any ideas?

[1] https://www.mercurial-scm.org/pipermail/mercurial/2018-June/050924.html

# 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.

from __future__ import absolute_import

import os
import sys

if sys.version_info[0] >= 3:
    from . import demandimportpy3 as demandimport
else:
    from . import demandimportpy2 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__',
    '_ssl', # conditional imports in the stdlib, issue1964
    '_sre', # issue4920
    'rfc822',
    'mimetools',
    'sqlalchemy.events', # has import-time side effects (issue5085)
    # setuptools 8 expects this module to explode early when not on windows
    'distutils.msvc9compiler',
    '__builtin__',
    'builtins',
    'urwid.command_map', # for pudb
}

_pypy = '__pypy__' in sys.builtin_module_names

if _pypy:
    # _ctypes.pointer is shadowed by "from ... import pointer" (PyPy 5)
    IGNORES.add('_ctypes.pointer')

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()