| # 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 six |
| import sys |
| |
| import astroid |
| from astroid.bases import Instance |
| |
| from pylint.interfaces import IAstroidChecker |
| from pylint.checkers import BaseChecker |
| from pylint.checkers import utils |
| |
| |
| if sys.version_info >= (3, 0): |
| OPEN_MODULE = '_io' |
| else: |
| OPEN_MODULE = '__builtin__' |
| |
| |
| def _check_mode_str(mode): |
| # check type |
| if not isinstance(mode, six.string_types): |
| return False |
| # check syntax |
| modes = set(mode) |
| _mode = "rwatb+U" |
| creating = False |
| if six.PY3: |
| _mode += "x" |
| 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 |
| updating = "+" in modes |
| text = "t" in modes |
| binary = "b" in modes |
| if "U" in modes: |
| if writing or appending or creating and six.PY3: |
| return False |
| reading = True |
| if not six.PY3: |
| binary = True |
| if text and binary: |
| return False |
| total = reading + writing + appending + (creating if six.PY3 else 0) |
| if total > 1: |
| return False |
| if not (reading or writing or appending or creating and six.PY3): |
| return False |
| # other 2.x constraints |
| if not six.PY3: |
| if "U" in mode: |
| mode = mode.replace("U", "") |
| if "r" not in mode: |
| mode = "r" + mode |
| return mode[0] in ("r", "w", "a", "U") |
| 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 datetetime.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.') |
| } |
| |
| @utils.check_messages('bad-open-mode', 'redundant-unittest-assert') |
| def visit_callfunc(self, node): |
| """Visit a CallFunc node.""" |
| if hasattr(node, 'func'): |
| infer = utils.safe_infer(node.func) |
| if infer: |
| if infer.root().name == OPEN_MODULE: |
| if getattr(node.func, 'name', None) in ('open', 'file'): |
| self._check_open_mode(node) |
| if infer.root().name == 'unittest.case': |
| self._check_redundant_assert(node, infer) |
| |
| @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_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 register(linter): |
| """required method to auto register this checker """ |
| linter.register_checker(StdlibChecker(linter)) |
