view mercurial/policy.py @ 39224:5e52b6da9c0c

tests: demonstrate a problem with renames on the p2 side of a conversion

I think this is related to the octopus merge being sloppy, and that's having a
cascading affect on the fixup merge.  If this change is made on p1 (specifically
with the 'Added parent file' commit), the failure doesn't occur.

The file modification with the rename doesn't seem to be necessary, but it's
what's happening in a production repo where I first noticed, so I left it.  This
is an example of the manifest divergence I'd been seeing, which wasn't fixed by
Yuya's recent changes.  This is separate from the changelog divergence I was
also seeing[1].  Probably nobody cares about bzr anymore, but this will also
affect git, since the octopus fixup code is in the hg sink.

[1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2018-August/120473.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, fall back to the pure modules so the in-place build can
# run without recompiling the C extensions. This will be overridden by
# __modulepolicy__ generated by setup.py.
policy = b'allow'
_packageprefs = {
    # policy: (versioned package, pure package)
    b'c': (r'cext', None),
    b'allow': (r'cext', r'pure'),
    b'cffi': (r'cffi', None),
    b'cffi-allow': (r'cffi', r'pure'),
    b'py': (None, r'pure'),
}

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 r'__pypy__' in sys.builtin_module_names:
    policy = b'cffi'

# Environment variable can always force settings.
if sys.version_info[0] >= 3:
    if r'HGMODULEPOLICY' in os.environ:
        policy = os.environ[r'HGMODULEPOLICY'].encode(r'utf-8')
else:
    policy = os.environ.get(r'HGMODULEPOLICY', policy)

def _importfrom(pkgname, modname):
    # from .<pkgname> import <modname> (where . is looked through this module)
    fakelocals = {}
    pkg = __import__(pkgname, globals(), fakelocals, [modname], level=1)
    try:
        fakelocals[modname] = mod = getattr(pkg, modname)
    except AttributeError:
        raise ImportError(r'cannot import name %s' % modname)
    # force import; fakelocals[modname] may be replaced with the real module
    getattr(mod, r'__doc__', None)
    return fakelocals[modname]

# keep in sync with "version" in C modules
_cextversions = {
    (r'cext', r'base85'): 1,
    (r'cext', r'bdiff'): 3,
    (r'cext', r'mpatch'): 1,
    (r'cext', r'osutil'): 4,
    (r'cext', r'parsers'): 8,
}

# map import request to other package or module
_modredirects = {
    (r'cext', r'charencode'): (r'cext', r'parsers'),
    (r'cffi', r'base85'): (r'pure', r'base85'),
    (r'cffi', r'charencode'): (r'pure', r'charencode'),
    (r'cffi', r'parsers'): (r'pure', r'parsers'),
}

def _checkmod(pkgname, modname, mod):
    expected = _cextversions.get((pkgname, modname))
    actual = getattr(mod, r'version', None)
    if actual != expected:
        raise ImportError(r'cannot import module %s.%s '
                          r'(expected version: %d, actual: %r)'
                          % (pkgname, modname, expected, actual))

def importmod(modname):
    """Import module according to policy and check API version"""
    try:
        verpkg, purepkg = _packageprefs[policy]
    except KeyError:
        raise ImportError(r'invalid HGMODULEPOLICY %r' % policy)
    assert verpkg or purepkg
    if verpkg:
        pn, mn = _modredirects.get((verpkg, modname), (verpkg, modname))
        try:
            mod = _importfrom(pn, mn)
            if pn == verpkg:
                _checkmod(pn, mn, mod)
            return mod
        except ImportError:
            if not purepkg:
                raise
    pn, mn = _modredirects.get((purepkg, modname), (purepkg, modname))
    return _importfrom(pn, mn)