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# Copyright (c) 2015-2018 Claudiu Popa <pcmanticore@gmail.com>
# Copyright (c) 2017 Derek Gustafson <degustaf@gmail.com>
# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
# For details: https://github.com/PyCQA/pylint/blob/master/COPYING
"""Checker for anything related to the async protocol (PEP 492)."""
import sys
import astroid
from astroid import exceptions
from pylint import checkers
from pylint.checkers import utils as checker_utils
from pylint import interfaces
from pylint import utils
class AsyncChecker(checkers.BaseChecker):
__implements__ = interfaces.IAstroidChecker
name = 'async'
msgs = {
'E1700': ('Yield inside async function',
'yield-inside-async-function',
'Used when an `yield` or `yield from` statement is '
'found inside an async function.',
{'minversion': (3, 5)}),
'E1701': ("Async context manager '%s' doesn't implement __aenter__ and __aexit__.",
'not-async-context-manager',
'Used when an async context manager is used with an object '
'that does not implement the async context management protocol.',
{'minversion': (3, 5)}),
}
def open(self):
self._ignore_mixin_members = utils.get_global_option(self, 'ignore-mixin-members')
@checker_utils.check_messages('yield-inside-async-function')
def visit_asyncfunctiondef(self, node):
for child in node.nodes_of_class(astroid.Yield):
if child.scope() is node and (sys.version_info[:2] == (3, 5) or
isinstance(child, astroid.YieldFrom)):
self.add_message('yield-inside-async-function', node=child)
@checker_utils.check_messages('not-async-context-manager')
def visit_asyncwith(self, node):
for ctx_mgr, _ in node.items:
infered = checker_utils.safe_infer(ctx_mgr)
if infered is None or infered is astroid.Uninferable:
continue
if isinstance(infered, astroid.Instance):
try:
infered.getattr('__aenter__')
infered.getattr('__aexit__')
except exceptions.NotFoundError:
if isinstance(infered, astroid.Instance):
# If we do not know the bases of this class,
# just skip it.
if not checker_utils.has_known_bases(infered):
continue
# Just ignore mixin classes.
if self._ignore_mixin_members:
if infered.name[-5:].lower() == 'mixin':
continue
else:
continue
self.add_message('not-async-context-manager',
node=node, args=(infered.name, ))
def register(linter):
"""required method to auto register this checker"""
linter.register_checker(AsyncChecker(linter))
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