# -*- coding: utf-8 -*- # Copyright (c) 2013-2014 LOGILAB S.A. (Paris, FRANCE) # Copyright (c) 2013-2014 Google, Inc. # Copyright (c) 2014-2018 Claudiu Popa # Copyright (c) 2014 Cosmin Poieana # Copyright (c) 2014 Vlad Temian # Copyright (c) 2014 Arun Persaud # Copyright (c) 2015 Cezar # Copyright (c) 2015 Chris Rebert # Copyright (c) 2015 Ionel Cristian Maries # Copyright (c) 2016 Jared Garst # Copyright (c) 2017 Renat Galimov # Copyright (c) 2017 Martin # Copyright (c) 2017 Christopher Zurcher # Copyright (c) 2017 Łukasz Rogalski # Copyright (c) 2018 Banjamin Freeman # Copyright (c) 2018 Ioana Tagirta # 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 """Checkers for various standard library functions.""" import sys import astroid from astroid.bases import Instance from astroid.node_classes import Const from pylint.interfaces import IAstroidChecker from pylint.checkers import BaseChecker from pylint.checkers import utils OPEN_FILES = {"open", "file"} UNITTEST_CASE = "unittest.case" THREADING_THREAD = "threading.Thread" COPY_COPY = "copy.copy" OS_ENVIRON = "os._Environ" ENV_GETTERS = {"os.getenv"} SUBPROCESS_POPEN = "subprocess.Popen" if sys.version_info >= (3, 0): OPEN_MODULE = "_io" else: OPEN_MODULE = "__builtin__" def _check_mode_str(mode): # check type if not isinstance(mode, str): return False # check syntax modes = set(mode) _mode = "rwatb+Ux" creating = "x" in modes if modes - set(_mode) or len(mode) > len(modes): return False # check logic reading = "r" in modes writing = "w" in modes appending = "a" in modes text = "t" in modes binary = "b" in modes if "U" in modes: if writing or appending or creating: return False reading = True if text and binary: return False total = reading + writing + appending + creating if total > 1: return False if not (reading or writing or appending or creating): return False return True class StdlibChecker(BaseChecker): __implements__ = (IAstroidChecker,) name = "stdlib" msgs = { "W1501": ( '"%s" is not a valid mode for open.', "bad-open-mode", "Python supports: r, w, a[, x] modes with b, +, " "and U (only with r) options. " "See http://docs.python.org/2/library/functions.html#open", ), "W1502": ( "Using datetime.time in a boolean context.", "boolean-datetime", "Using datetime.time in a boolean context can hide " "subtle bugs when the time they represent matches " "midnight UTC. This behaviour was fixed in Python 3.5. " "See http://bugs.python.org/issue13936 for reference.", {"maxversion": (3, 5)}, ), "W1503": ( "Redundant use of %s with constant " "value %r", "redundant-unittest-assert", "The first argument of assertTrue and assertFalse is " "a condition. If a constant is passed as parameter, that " "condition will be always true. In this case a warning " "should be emitted.", ), "W1505": ( "Using deprecated method %s()", "deprecated-method", "The method is marked as deprecated and will be removed in " "a future version of Python. Consider looking for an " "alternative in the documentation.", ), "W1506": ( "threading.Thread needs the target function", "bad-thread-instantiation", "The warning is emitted when a threading.Thread class " "is instantiated without the target function being passed. " "By default, the first parameter is the group param, not the target param. ", ), "W1507": ( "Using copy.copy(os.environ). Use os.environ.copy() " "instead. ", "shallow-copy-environ", "os.environ is not a dict object but proxy object, so " "shallow copy has still effects on original object. " "See https://bugs.python.org/issue15373 for reference. ", ), "E1507": ( "%s does not support %s type argument", "invalid-envvar-value", "Env manipulation functions support only string type arguments. " "See https://docs.python.org/3/library/os.html#os.getenv. ", ), "W1508": ( "%s default type is %s. Expected str or None.", "invalid-envvar-default", "Env manipulation functions return None or str values. " "Supplying anything different as a default may cause bugs. " "See https://docs.python.org/3/library/os.html#os.getenv. ", ), "W1509": ( "Using preexec_fn keyword which may be unsafe in the presence " "of threads", "subprocess-popen-preexec-fn", "The preexec_fn parameter is not safe to use in the presence " "of threads in your application. The child process could " "deadlock before exec is called. If you must use it, keep it " "trivial! Minimize the number of libraries you call into." "https://docs.python.org/3/library/subprocess.html#popen-constructor", ), } deprecated = { 0: [ "cgi.parse_qs", "cgi.parse_qsl", "ctypes.c_buffer", "distutils.command.register.register.check_metadata", "distutils.command.sdist.sdist.check_metadata", "tkinter.Misc.tk_menuBar", "tkinter.Menu.tk_bindForTraversal", ], 2: { (2, 6, 0): [ "commands.getstatus", "os.popen2", "os.popen3", "os.popen4", "macostools.touched", ], (2, 7, 0): [ "unittest.case.TestCase.assertEquals", "unittest.case.TestCase.assertNotEquals", "unittest.case.TestCase.assertAlmostEquals", "unittest.case.TestCase.assertNotAlmostEquals", "unittest.case.TestCase.assert_", "xml.etree.ElementTree.Element.getchildren", "xml.etree.ElementTree.Element.getiterator", "xml.etree.ElementTree.XMLParser.getiterator", "xml.etree.ElementTree.XMLParser.doctype", ], }, 3: { (3, 0, 0): [ "inspect.getargspec", "unittest.case.TestCase._deprecate.deprecated_func", ], (3, 1, 0): [ "base64.encodestring", "base64.decodestring", "ntpath.splitunc", ], (3, 2, 0): [ "cgi.escape", "configparser.RawConfigParser.readfp", "xml.etree.ElementTree.Element.getchildren", "xml.etree.ElementTree.Element.getiterator", "xml.etree.ElementTree.XMLParser.getiterator", "xml.etree.ElementTree.XMLParser.doctype", ], (3, 3, 0): [ "inspect.getmoduleinfo", "logging.warn", "logging.Logger.warn", "logging.LoggerAdapter.warn", "nntplib._NNTPBase.xpath", "platform.popen", ], (3, 4, 0): [ "importlib.find_loader", "plistlib.readPlist", "plistlib.writePlist", "plistlib.readPlistFromBytes", "plistlib.writePlistToBytes", ], (3, 4, 4): ["asyncio.tasks.async"], (3, 5, 0): [ "fractions.gcd", "inspect.getargvalues", "inspect.formatargspec", "inspect.formatargvalues", "inspect.getcallargs", "platform.linux_distribution", "platform.dist", ], (3, 6, 0): ["importlib._bootstrap_external.FileLoader.load_module"], }, } def _check_bad_thread_instantiation(self, node): if not node.kwargs and not node.keywords and len(node.args) <= 1: self.add_message("bad-thread-instantiation", node=node) def _check_for_preexec_fn_in_Popen(self, node): if node.keywords: for keyword in node.keywords: if keyword.arg == "preexec_fn": self.add_message("subprocess-popen-preexec-fn", node=node) def _check_shallow_copy_environ(self, node): arg = utils.get_argument_from_call(node, position=0) for inferred in arg.inferred(): if inferred.qname() == OS_ENVIRON: self.add_message("shallow-copy-environ", node=node) break @utils.check_messages( "bad-open-mode", "redundant-unittest-assert", "deprecated-method", "bad-thread-instantiation", "shallow-copy-environ", "invalid-envvar-value", "invalid-envvar-default", "subprocess-popen-preexec-fn", ) def visit_call(self, node): """Visit a Call node.""" try: for inferred in node.func.infer(): if inferred is astroid.Uninferable: continue elif inferred.root().name == OPEN_MODULE: if getattr(node.func, "name", None) in OPEN_FILES: self._check_open_mode(node) elif inferred.root().name == UNITTEST_CASE: self._check_redundant_assert(node, inferred) elif isinstance(inferred, astroid.ClassDef): if inferred.qname() == THREADING_THREAD: self._check_bad_thread_instantiation(node) elif inferred.qname() == SUBPROCESS_POPEN: self._check_for_preexec_fn_in_Popen(node) elif isinstance(inferred, astroid.FunctionDef): name = inferred.qname() if name == COPY_COPY: self._check_shallow_copy_environ(node) elif name in ENV_GETTERS: self._check_env_function(node, inferred) self._check_deprecated_method(node, inferred) except astroid.InferenceError: return @utils.check_messages("boolean-datetime") def visit_unaryop(self, node): if node.op == "not": self._check_datetime(node.operand) @utils.check_messages("boolean-datetime") def visit_if(self, node): self._check_datetime(node.test) @utils.check_messages("boolean-datetime") def visit_ifexp(self, node): self._check_datetime(node.test) @utils.check_messages("boolean-datetime") def visit_boolop(self, node): for value in node.values: self._check_datetime(value) def _check_deprecated_method(self, node, inferred): py_vers = sys.version_info[0] if isinstance(node.func, astroid.Attribute): func_name = node.func.attrname elif isinstance(node.func, astroid.Name): func_name = node.func.name else: # Not interested in other nodes. return # Reject nodes which aren't of interest to us. acceptable_nodes = ( astroid.BoundMethod, astroid.UnboundMethod, astroid.FunctionDef, ) if not isinstance(inferred, acceptable_nodes): return qname = inferred.qname() if qname in self.deprecated[0]: self.add_message("deprecated-method", node=node, args=(func_name,)) else: for since_vers, func_list in self.deprecated[py_vers].items(): if since_vers <= sys.version_info and qname in func_list: self.add_message("deprecated-method", node=node, args=(func_name,)) break def _check_redundant_assert(self, node, infer): if ( isinstance(infer, astroid.BoundMethod) and node.args and isinstance(node.args[0], astroid.Const) and infer.name in ["assertTrue", "assertFalse"] ): self.add_message( "redundant-unittest-assert", args=(infer.name, node.args[0].value), node=node, ) def _check_datetime(self, node): """ Check that a datetime was infered. If so, emit boolean-datetime warning. """ try: infered = next(node.infer()) except astroid.InferenceError: return if isinstance(infered, Instance) and infered.qname() == "datetime.time": self.add_message("boolean-datetime", node=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") except utils.NoSuchArgumentError: return if mode_arg: mode_arg = utils.safe_infer(mode_arg) if isinstance(mode_arg, astroid.Const) and not _check_mode_str( mode_arg.value ): self.add_message("bad-open-mode", node=node, args=mode_arg.value) def _check_env_function(self, node, infer): env_name_kwarg = "key" env_value_kwarg = "default" if node.keywords: kwargs = {keyword.arg: keyword.value for keyword in node.keywords} else: kwargs = None if node.args: env_name_arg = node.args[0] elif kwargs and env_name_kwarg in kwargs: env_name_arg = kwargs[env_name_kwarg] else: env_name_arg = None if env_name_arg: self._check_invalid_envvar_value( node=node, message="invalid-envvar-value", call_arg=utils.safe_infer(env_name_arg), infer=infer, allow_none=False, ) if len(node.args) == 2: env_value_arg = node.args[1] elif kwargs and env_value_kwarg in kwargs: env_value_arg = kwargs[env_value_kwarg] else: env_value_arg = None if env_value_arg: self._check_invalid_envvar_value( node=node, infer=infer, message="invalid-envvar-default", call_arg=utils.safe_infer(env_value_arg), allow_none=True, ) def _check_invalid_envvar_value(self, node, infer, message, call_arg, allow_none): if call_arg in (astroid.Uninferable, None): return name = infer.qname() if isinstance(call_arg, Const): emit = False if call_arg.value is None: emit = not allow_none elif not isinstance(call_arg.value, str): emit = True if emit: self.add_message(message, node=node, args=(name, call_arg.pytype())) else: self.add_message(message, node=node, args=(name, call_arg.pytype())) def register(linter): """required method to auto register this checker """ linter.register_checker(StdlibChecker(linter))