Add string_format pylint plugin.

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Matt Martz 2018-01-05 15:35:05 -08:00 committed by Matt Clay
parent a9fe30e34b
commit 8c1353537d

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# (c) 2018, Matt Martz <matt@sivel.net>
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
# -*- coding: utf-8 -*-
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type
import sys
import six
import astroid
from pylint.interfaces import IAstroidChecker
from pylint.checkers import BaseChecker
from pylint.checkers import utils
from pylint.checkers.utils import check_messages
from pylint.checkers.strings import parse_format_method_string
_PY3K = sys.version_info[:2] >= (3, 0)
MSGS = {
'E9305': ("Format string contains automatic field numbering "
"specification",
"ansible-format-automatic-specification",
"Used when a PEP 3101 format string contains automatic "
"field numbering (e.g. '{}').",
{'minversion': (2, 6)}),
'E9390': ("bytes object has no .format attribute",
"ansible-no-format-on-bytestring",
"Used when a bytestring was used as a PEP 3101 format string "
"as Python3 bytestrings do not have a .format attribute",
{'minversion': (3, 0)}),
}
class AnsibleStringFormatChecker(BaseChecker):
"""Checks string formatting operations to ensure that the format string
is valid and the arguments match the format string.
"""
__implements__ = (IAstroidChecker,)
name = 'string'
msgs = MSGS
@check_messages(*(MSGS.keys()))
def visit_call(self, node):
func = utils.safe_infer(node.func)
if (isinstance(func, astroid.BoundMethod)
and isinstance(func.bound, astroid.Instance)
and func.bound.name in ('str', 'unicode', 'bytes')):
if func.name == 'format':
self._check_new_format(node, func)
def _check_new_format(self, node, func):
""" Check the new string formatting """
if (isinstance(node.func, astroid.Attribute)
and not isinstance(node.func.expr, astroid.Const)):
return
try:
strnode = next(func.bound.infer())
except astroid.InferenceError:
return
if not isinstance(strnode, astroid.Const):
return
if _PY3K and isinstance(strnode.value, six.binary_type):
self.add_message('ansible-no-format-on-bytestring', node=node)
return
if not isinstance(strnode.value, six.string_types):
return
if node.starargs or node.kwargs:
return
try:
fields, num_args, manual_pos = parse_format_method_string(strnode.value)
except utils.IncompleteFormatString:
return
if num_args:
self.add_message('ansible-format-automatic-specification',
node=node)
return
def register(linter):
"""required method to auto register this checker """
linter.register_checker(AnsibleStringFormatChecker(linter))