Mercurial > hg
view i18n/hggettext @ 29642:8960fcb76ca4 stable
demandimport: avoid infinite recursion at actual module importing (issue5304)
Before this patch, importing C module on Windows environment causes
infinite recursion call, if py2exe is used with -b2 option.
At importing C module "a.b", extra hooking by zipextimporter of py2exe
causes:
0. assumption before accessing "b" of "a":
- built-in module object is created for "a",
(= "a" is actually imported)
- _demandmod is created for "a.b" as a proxy object, and
(= "a.b" is not yet imported)
- an attribute "b" of "a" is initialized by the latter
1. invocation of __import__ via _hgextimport() in _demandmod._load()
for "a.b" implies _demandimport() for "a.b"
This is unintentional, because _demandmod might be returned by
_hgextimport() instead of built-in module object.
2. _demandimport() at (1) is invoked with not context of "a", but
context of zipextimporter
Just after invocation of _hgextimport() in _demandimport(), an
attribute "b" of the built-in module object for "a" is still
bound to the proxy object for "a.b", because context of "a" isn't
updated by actual importing "a.b". even though the built-in
module object for "a.b" already appears in sys.modules.
Therefore, chainmodules() returns _demandmod for "a.b", which is
gotten from the attribute "b" of "a".
3. processfromitem() on "a.b" causes _demandmod._load() for "a.b"
again
_demandimport() takes context of "a" in this case.
Therefore, attributes below are bound to built-in module object
for "a.b", as expected:
- "b" of built-in module object for "a"
- _module of _demandmod for "a.b"
4. but _demandimport() invoked at (1) returns _demandmod object
because _demandimport() just returns the object returned by
chainmodules() at (3) above.
5. then, _demandmod._load() causes infinite recursion call
_demandimport() returns _demandmod for "a.b", and it is "self" at
_demandmod._load().
To avoid infinite recursion at actual module importing, this patch
uses self._module, if _hgextimport() returns _demandmod itself. If
_demandmod._module isn't yet bound at this point, execution should be
aborted, because actual importing failed.
In this patch, _demandmod._module is examined not on _demandimport()
side, but on _demandmod._load() side, because:
- the former has some exit points
- only the latter uses _hgextimport(), except for _demandimport()
BTW, this issue occurs only in the code path for non .py/.pyc files in
zipextimporter (strictly speaking, in _memimporter) of py2exe.
Even if zipextimporter is enabled, .py/.pyc files are handled by
zipimporter, and it doesn't imply unintentional _demandimport() at
invocation of __import__ via _hgextimport().
author | FUJIWARA Katsunori <foozy@lares.dti.ne.jp> |
---|---|
date | Sun, 31 Jul 2016 05:39:59 +0900 |
parents | de28dedd1ff1 |
children | 041fecbb588a |
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#!/usr/bin/env python # # hggettext - carefully extract docstrings for Mercurial # # Copyright 2009 Matt Mackall <mpm@selenic.com> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. # The normalize function is taken from pygettext which is distributed # with Python under the Python License, which is GPL compatible. """Extract docstrings from Mercurial commands. Compared to pygettext, this script knows about the cmdtable and table dictionaries used by Mercurial, and will only extract docstrings from functions mentioned therein. Use xgettext like normal to extract strings marked as translatable and join the message cataloges to get the final catalog. """ from __future__ import absolute_import, print_function import inspect import os import sys def escape(s): # The order is important, the backslash must be escaped first # since the other replacements introduce new backslashes # themselves. s = s.replace('\\', '\\\\') s = s.replace('\n', '\\n') s = s.replace('\r', '\\r') s = s.replace('\t', '\\t') s = s.replace('"', '\\"') return s def normalize(s): # This converts the various Python string types into a format that # is appropriate for .po files, namely much closer to C style. lines = s.split('\n') if len(lines) == 1: s = '"' + escape(s) + '"' else: if not lines[-1]: del lines[-1] lines[-1] = lines[-1] + '\n' lines = map(escape, lines) lineterm = '\\n"\n"' s = '""\n"' + lineterm.join(lines) + '"' return s def poentry(path, lineno, s): return ('#: %s:%d\n' % (path, lineno) + 'msgid %s\n' % normalize(s) + 'msgstr ""\n') def offset(src, doc, name, default): """Compute offset or issue a warning on stdout.""" # Backslashes in doc appear doubled in src. end = src.find(doc.replace('\\', '\\\\')) if end == -1: # This can happen if the docstring contains unnecessary escape # sequences such as \" in a triple-quoted string. The problem # is that \" is turned into " and so doc wont appear in src. sys.stderr.write("warning: unknown offset in %s, assuming %d lines\n" % (name, default)) return default else: return src.count('\n', 0, end) def importpath(path): """Import a path like foo/bar/baz.py and return the baz module.""" if path.endswith('.py'): path = path[:-3] if path.endswith('/__init__'): path = path[:-9] path = path.replace('/', '.') mod = __import__(path) for comp in path.split('.')[1:]: mod = getattr(mod, comp) return mod def docstrings(path): """Extract docstrings from path. This respects the Mercurial cmdtable/table convention and will only extract docstrings from functions mentioned in these tables. """ mod = importpath(path) if mod.__doc__: src = open(path).read() lineno = 1 + offset(src, mod.__doc__, path, 7) print(poentry(path, lineno, mod.__doc__)) functions = list(getattr(mod, 'i18nfunctions', [])) functions = [(f, True) for f in functions] cmdtable = getattr(mod, 'cmdtable', {}) if not cmdtable: # Maybe we are processing mercurial.commands? cmdtable = getattr(mod, 'table', {}) functions.extend((c[0], False) for c in cmdtable.itervalues()) for func, rstrip in functions: if func.__doc__: src = inspect.getsource(func) name = "%s.%s" % (path, func.__name__) lineno = func.func_code.co_firstlineno doc = func.__doc__ if rstrip: doc = doc.rstrip() lineno += offset(src, doc, name, 1) print(poentry(path, lineno, doc)) def rawtext(path): src = open(path).read() print(poentry(path, 1, src)) if __name__ == "__main__": # It is very important that we import the Mercurial modules from # the source tree where hggettext is executed. Otherwise we might # accidentally import and extract strings from a Mercurial # installation mentioned in PYTHONPATH. sys.path.insert(0, os.getcwd()) from mercurial import demandimport; demandimport.enable() for path in sys.argv[1:]: if path.endswith('.txt'): rawtext(path) else: docstrings(path)