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# Copyright 2012 Google Inc.
#
# http://www.logilab.fr/ -- mailto:contact@logilab.fr
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
"""Checkers for various standard library functions."""
import re
import sys
import astroid
from pylint.interfaces import IAstroidChecker
from pylint.checkers import BaseChecker
from pylint.checkers import utils
_VALID_OPEN_MODE_REGEX = r'^(r?U|[rwa]\+?b?)$'
if sys.version_info >= (3, 0):
OPEN_MODULE = '_io'
else:
OPEN_MODULE = '__builtin__'
class OpenModeChecker(BaseChecker):
__implements__ = (IAstroidChecker,)
name = 'open_mode'
msgs = {
'W1501': ('"%s" is not a valid mode for open.',
'bad-open-mode',
'Python supports: r, w, a modes with b, +, and U options. '
'See http://docs.python.org/2/library/functions.html#open'),
}
@utils.check_messages('W1501')
def visit_callfunc(self, node):
"""Visit a CallFunc node."""
if hasattr(node, 'func'):
infer = utils.safe_infer(node.func)
if infer and infer.root().name == OPEN_MODULE:
if getattr(node.func, 'name', None) in ('open', 'file'):
self._check_open_mode(node)
def _check_open_mode(self, node):
"""Check that the mode argument of an open or file call is valid."""
try:
mode_arg = utils.get_argument_from_call(node, position=1, keyword='mode')
if mode_arg:
mode_arg = utils.safe_infer(mode_arg)
if (isinstance(mode_arg, astroid.Const)
and not re.match(_VALID_OPEN_MODE_REGEX, mode_arg.value)):
self.add_message('W1501', node=node, args=(mode_arg.value))
except (utils.NoSuchArgumentError, TypeError):
pass
def register(linter):
"""required method to auto register this checker """
linter.register_checker(OpenModeChecker(linter))
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