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
line wrap: on
line source

#!/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)