Mercurial > hg
view mercurial/policy.py @ 44651:00e0c5c06ed5
pycompat: change argv conversion semantics
Use of os.fsencode() to convert Python's sys.argv back to bytes
was not correct because it isn't the logically inverse operation
from what CPython was doing under the hood.
This commit changes the logic for doing the str -> bytes
conversion. This required a separate implementation for
POSIX and Windows.
The Windows behavior is arguably not ideal. The previous
behavior on Windows was leading to failing tests, such as
test-http-branchmap.t, which defines a utf-8 branch name
via a command argument. Previously, Mercurial's argument
parser looked to be receiving wchar_t bytes in some cases.
After this commit, behavior on Windows is compatible with
Python 2, where CPython did not implement `int wmain()` and
Windows was performing a Unicode to ANSI conversion on the
wchar_t native command line.
Arguably better behavior on Windows would be for Mercurial to
preserve the original Unicode sequence coming from Python and
to wrap this in a bytes-like type so we can round trip safely.
But, this would be new, backwards incompatible behavior. My
goal for this commit was to converge Mercurial behavior on
Python 3 on Windows to fix busted tests. And I believe I was
successful, as this commit fixes 9 tests on my Windows
machine and 14 tests in the AWS CI environment!
Differential Revision: https://phab.mercurial-scm.org/D8337
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sat, 28 Mar 2020 12:18:58 -0700 |
parents | b56de57c45ce |
children | 61e7464477ac |
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# policy.py - module policy logic for Mercurial. # # Copyright 2015 Gregory Szorc <gregory.szorc@gmail.com> # # 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 from .pycompat import getattr # Rules for how modules can be loaded. Values are: # # c - require C extensions # rust+c - require Rust and C extensions # rust+c-allow - allow Rust and C extensions with fallback to pure Python # for each # 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': ('cext', None), b'allow': ('cext', 'pure'), b'cffi': ('cffi', None), b'cffi-allow': ('cffi', 'pure'), b'py': (None, 'pure'), # For now, rust policies impact importrust only b'rust+c': ('cext', None), b'rust+c-allow': ('cext', '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 '__pypy__' in sys.builtin_module_names: policy = b'cffi' # Environment variable can always force settings. if sys.version_info[0] >= 3: if 'HGMODULEPOLICY' in os.environ: policy = os.environ['HGMODULEPOLICY'].encode('utf-8') else: policy = os.environ.get('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('cannot import name %s' % modname) # force import; fakelocals[modname] may be replaced with the real module getattr(mod, '__doc__', None) return fakelocals[modname] # keep in sync with "version" in C modules _cextversions = { ('cext', 'base85'): 1, ('cext', 'bdiff'): 3, ('cext', 'mpatch'): 1, ('cext', 'osutil'): 4, ('cext', 'parsers'): 16, } # map import request to other package or module _modredirects = { ('cext', 'charencode'): ('cext', 'parsers'), ('cffi', 'base85'): ('pure', 'base85'), ('cffi', 'charencode'): ('pure', 'charencode'), ('cffi', 'parsers'): ('pure', 'parsers'), } def _checkmod(pkgname, modname, mod): expected = _cextversions.get((pkgname, modname)) actual = getattr(mod, 'version', None) if actual != expected: raise ImportError( 'cannot import module %s.%s ' '(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('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) def _isrustpermissive(): """Assuming the policy is a Rust one, tell if it's permissive.""" return policy.endswith(b'-allow') def importrust(modname, member=None, default=None): """Import Rust module according to policy and availability. If policy isn't a Rust one, this returns `default`. If either the module or its member is not available, this returns `default` if policy is permissive and raises `ImportError` if not. """ if not policy.startswith(b'rust'): return default try: mod = _importfrom('rustext', modname) except ImportError: if _isrustpermissive(): return default raise if member is None: return mod try: return getattr(mod, member) except AttributeError: if _isrustpermissive(): return default raise ImportError("Cannot import name %s" % member)