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| 1 # Copyright 2012 Google Inc. |
| 2 # |
| 3 # http://www.logilab.fr/ -- mailto:contact@logilab.fr |
| 4 # This program is free software; you can redistribute it and/or modify it under |
| 5 # the terms of the GNU General Public License as published by the Free Software |
| 6 # Foundation; either version 2 of the License, or (at your option) any later |
| 7 # version. |
| 8 # |
| 9 # This program is distributed in the hope that it will be useful, but WITHOUT |
| 10 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| 11 # FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details |
| 12 # |
| 13 # You should have received a copy of the GNU General Public License along with |
| 14 # this program; if not, write to the Free Software Foundation, Inc., |
| 15 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
| 16 """Checkers for various standard library functions.""" |
| 17 |
| 18 import re |
| 19 import six |
| 20 import sys |
| 21 |
| 22 import astroid |
| 23 from astroid.bases import Instance |
| 24 |
| 25 from pylint.interfaces import IAstroidChecker |
| 26 from pylint.checkers import BaseChecker |
| 27 from pylint.checkers import utils |
| 28 |
| 29 |
| 30 if sys.version_info >= (3, 0): |
| 31 OPEN_MODULE = '_io' |
| 32 else: |
| 33 OPEN_MODULE = '__builtin__' |
| 34 |
| 35 |
| 36 def _check_mode_str(mode): |
| 37 # check type |
| 38 if not isinstance(mode, six.string_types): |
| 39 return False |
| 40 # check syntax |
| 41 modes = set(mode) |
| 42 _mode = "rwatb+U" |
| 43 creating = False |
| 44 if six.PY3: |
| 45 _mode += "x" |
| 46 creating = "x" in modes |
| 47 if modes - set(_mode) or len(mode) > len(modes): |
| 48 return False |
| 49 # check logic |
| 50 reading = "r" in modes |
| 51 writing = "w" in modes |
| 52 appending = "a" in modes |
| 53 updating = "+" in modes |
| 54 text = "t" in modes |
| 55 binary = "b" in modes |
| 56 if "U" in modes: |
| 57 if writing or appending or creating and six.PY3: |
| 58 return False |
| 59 reading = True |
| 60 if not six.PY3: |
| 61 binary = True |
| 62 if text and binary: |
| 63 return False |
| 64 total = reading + writing + appending + (creating if six.PY3 else 0) |
| 65 if total > 1: |
| 66 return False |
| 67 if not (reading or writing or appending or creating and six.PY3): |
| 68 return False |
| 69 # other 2.x constraints |
| 70 if not six.PY3: |
| 71 if "U" in mode: |
| 72 mode = mode.replace("U", "") |
| 73 if "r" not in mode: |
| 74 mode = "r" + mode |
| 75 return mode[0] in ("r", "w", "a", "U") |
| 76 return True |
| 77 |
| 78 |
| 79 class StdlibChecker(BaseChecker): |
| 80 __implements__ = (IAstroidChecker,) |
| 81 name = 'stdlib' |
| 82 |
| 83 msgs = { |
| 84 'W1501': ('"%s" is not a valid mode for open.', |
| 85 'bad-open-mode', |
| 86 'Python supports: r, w, a[, x] modes with b, +, ' |
| 87 'and U (only with r) options. ' |
| 88 'See http://docs.python.org/2/library/functions.html#open'), |
| 89 'W1502': ('Using datetime.time in a boolean context.', |
| 90 'boolean-datetime', |
| 91 'Using datetetime.time in a boolean context can hide ' |
| 92 'subtle bugs when the time they represent matches ' |
| 93 'midnight UTC. This behaviour was fixed in Python 3.5. ' |
| 94 'See http://bugs.python.org/issue13936 for reference.', |
| 95 {'maxversion': (3, 5)}), |
| 96 'W1503': ('Redundant use of %s with constant ' |
| 97 'value %r', |
| 98 'redundant-unittest-assert', |
| 99 'The first argument of assertTrue and assertFalse is' |
| 100 'a condition. If a constant is passed as parameter, that' |
| 101 'condition will be always true. In this case a warning ' |
| 102 'should be emitted.') |
| 103 } |
| 104 |
| 105 @utils.check_messages('bad-open-mode', 'redundant-unittest-assert') |
| 106 def visit_callfunc(self, node): |
| 107 """Visit a CallFunc node.""" |
| 108 if hasattr(node, 'func'): |
| 109 infer = utils.safe_infer(node.func) |
| 110 if infer: |
| 111 if infer.root().name == OPEN_MODULE: |
| 112 if getattr(node.func, 'name', None) in ('open', 'file'): |
| 113 self._check_open_mode(node) |
| 114 if infer.root().name == 'unittest.case': |
| 115 self._check_redundant_assert(node, infer) |
| 116 |
| 117 @utils.check_messages('boolean-datetime') |
| 118 def visit_unaryop(self, node): |
| 119 if node.op == 'not': |
| 120 self._check_datetime(node.operand) |
| 121 |
| 122 @utils.check_messages('boolean-datetime') |
| 123 def visit_if(self, node): |
| 124 self._check_datetime(node.test) |
| 125 |
| 126 @utils.check_messages('boolean-datetime') |
| 127 def visit_ifexp(self, node): |
| 128 self._check_datetime(node.test) |
| 129 |
| 130 @utils.check_messages('boolean-datetime') |
| 131 def visit_boolop(self, node): |
| 132 for value in node.values: |
| 133 self._check_datetime(value) |
| 134 |
| 135 def _check_redundant_assert(self, node, infer): |
| 136 if (isinstance(infer, astroid.BoundMethod) and |
| 137 node.args and isinstance(node.args[0], astroid.Const) and |
| 138 infer.name in ['assertTrue', 'assertFalse']): |
| 139 self.add_message('redundant-unittest-assert', |
| 140 args=(infer.name, node.args[0].value, ), |
| 141 node=node) |
| 142 |
| 143 def _check_datetime(self, node): |
| 144 """ Check that a datetime was infered. |
| 145 If so, emit boolean-datetime warning. |
| 146 """ |
| 147 try: |
| 148 infered = next(node.infer()) |
| 149 except astroid.InferenceError: |
| 150 return |
| 151 if (isinstance(infered, Instance) and |
| 152 infered.qname() == 'datetime.time'): |
| 153 self.add_message('boolean-datetime', node=node) |
| 154 |
| 155 |
| 156 def _check_open_mode(self, node): |
| 157 """Check that the mode argument of an open or file call is valid.""" |
| 158 try: |
| 159 mode_arg = utils.get_argument_from_call(node, position=1, |
| 160 keyword='mode') |
| 161 except utils.NoSuchArgumentError: |
| 162 return |
| 163 if mode_arg: |
| 164 mode_arg = utils.safe_infer(mode_arg) |
| 165 if (isinstance(mode_arg, astroid.Const) |
| 166 and not _check_mode_str(mode_arg.value)): |
| 167 self.add_message('bad-open-mode', node=node, |
| 168 args=mode_arg.value) |
| 169 |
| 170 |
| 171 def register(linter): |
| 172 """required method to auto register this checker """ |
| 173 linter.register_checker(StdlibChecker(linter)) |
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