Mercurial > hg
view mercurial/__init__.py @ 27275:f2cd240f2f7c
ui: add a 'deprecwarn' helper to issue deprecation warnings
As discussed on the list, we are adding an official way to keep old API around
for a short time in order to help third party developer to catch up. The
deprecated API will issue developer warning (issued by default during test runs)
to warn extensions authors that they need to upgrade their code without
instantaneously breaking tool chains and normal users.
The version is passed as an explicit argument so that developer think about it
and a potential future script can automatically check for it.
This is not build as a decorator because accessing the 'ui' instance will likely
be different each time. The message is also free form because deprecated API are
replaced in a variety of ways. I'm not super happy about the final rendering of
that message, but this is a developer oriented warning and I would like to move
forward.
author | Pierre-Yves David <pierre-yves.david@fb.com> |
---|---|
date | Sat, 05 Dec 2015 23:05:49 -0800 |
parents | 30a20167ae29 |
children | 17b85d739b62 |
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# __init__.py - Startup and module loading 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 imp import os import sys import zipimport __all__ = [] # 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 modulepolicy = '@MODULELOADPOLICY@' # By default, require the C extensions for performance reasons. if modulepolicy == '@' 'MODULELOADPOLICY' '@': modulepolicy = 'c' # 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: modulepolicy = 'py' # Environment variable can always force settings. modulepolicy = os.environ.get('HGMODULEPOLICY', modulepolicy) # Modules that have both Python and C implementations. See also the # set of .py files under mercurial/pure/. _dualmodules = set([ 'mercurial.base85', 'mercurial.bdiff', 'mercurial.diffhelpers', 'mercurial.mpatch', 'mercurial.osutil', 'mercurial.parsers', ]) class hgimporter(object): """Object that conforms to import hook interface defined in PEP-302.""" def find_module(self, name, path=None): # We only care about modules that have both C and pure implementations. if name in _dualmodules: return self return None def load_module(self, name): mod = sys.modules.get(name, None) if mod: return mod mercurial = sys.modules['mercurial'] # The zip importer behaves sufficiently differently from the default # importer to warrant its own code path. loader = getattr(mercurial, '__loader__', None) if isinstance(loader, zipimport.zipimporter): def ziploader(*paths): """Obtain a zipimporter for a directory under the main zip.""" path = os.path.join(loader.archive, *paths) zl = sys.path_importer_cache.get(path) if not zl: zl = zipimport.zipimporter(path) return zl try: if modulepolicy == 'py': raise ImportError() zl = ziploader('mercurial') mod = zl.load_module(name) # Unlike imp, ziploader doesn't expose module metadata that # indicates the type of module. So just assume what we found # is OK (even though it could be a pure Python module). except ImportError: if modulepolicy == 'c': raise zl = ziploader('mercurial', 'pure') mod = zl.load_module(name) sys.modules[name] = mod return mod # Unlike the default importer which searches special locations and # sys.path, we only look in the directory where "mercurial" was # imported from. # imp.find_module doesn't support submodules (modules with "."). # Instead you have to pass the parent package's __path__ attribute # as the path argument. stem = name.split('.')[-1] try: if modulepolicy == 'py': raise ImportError() modinfo = imp.find_module(stem, mercurial.__path__) # The Mercurial installer used to copy files from # mercurial/pure/*.py to mercurial/*.py. Therefore, it's possible # for some installations to have .py files under mercurial/*. # Loading Python modules when we expected C versions could result # in a) poor performance b) loading a version from a previous # Mercurial version, potentially leading to incompatibility. Either # scenario is bad. So we verify that modules loaded from # mercurial/* are C extensions. If the current policy allows the # loading of .py modules, the module will be re-imported from # mercurial/pure/* below. if modinfo[2][2] != imp.C_EXTENSION: raise ImportError('.py version of %s found where C ' 'version should exist' % name) except ImportError: if modulepolicy == 'c': raise # Could not load the C extension and pure Python is allowed. So # try to load them. from . import pure modinfo = imp.find_module(stem, pure.__path__) if not modinfo: raise ImportError('could not find mercurial module %s' % name) mod = imp.load_module(name, *modinfo) sys.modules[name] = mod return mod # We automagically register our custom importer as a side-effect of loading. # This is necessary to ensure that any entry points are able to import # mercurial.* modules without having to perform this registration themselves. if not any(isinstance(x, hgimporter) for x in sys.meta_path): # meta_path is used before any implicit finders and before sys.path. sys.meta_path.insert(0, hgimporter())