# Copyright (c) 2015-2017 Claudiu Popa # Copyright (c) 2017 Derek Gustafson # 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.YES: 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))