diff options
Diffstat (limited to 'pylint/checkers/base.py')
| -rw-r--r-- | pylint/checkers/base.py | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/pylint/checkers/base.py b/pylint/checkers/base.py index 74a1f64..e8a4396 100644 --- a/pylint/checkers/base.py +++ b/pylint/checkers/base.py @@ -1843,6 +1843,36 @@ class ElifChecker(BaseTokenChecker): (len(self._nested_blocks), self.config.max_nested_blocks)) +class NotChecker(_BasicChecker): + """checks for nots too many in comparison expressions + + - "not not" should trigger a warning + - "not" followed by a comparison should trigger a warning + """ + msgs = {'W0126': ('One not too many in "%s", should be "%s"', + 'unneeded-not', + 'Used when a boolean expression contains an unneeded ' + 'negation.'), + } + + @check_messages('unneeded-not') + def visit_unaryop(self, node): + if node.op != 'not': + return + operand = node.operand + if isinstance(operand, astroid.UnaryOp) and operand.op == 'not': + self.add_message('unneeded-not', node=node, + args=(node.as_string(), + operand.operand.as_string())) + elif isinstance(operand, astroid.Compare): + operator, _ = operand.ops[0] + reverse_op = {'<': '>=', '<=': '>', '>': '<=', '>=': '<', + '==': '!=', '!=': '=='} + suggestion = node.as_string().replace('not ', '').replace( + operator, reverse_op[operator]) + self.add_message('unneeded-not', node=node, + args=(node.as_string(), suggestion)) + def register(linter): """required method to auto register this checker""" @@ -1853,5 +1883,6 @@ def register(linter): linter.register_checker(PassChecker(linter)) linter.register_checker(LambdaForComprehensionChecker(linter)) linter.register_checker(ComparisonChecker(linter)) + linter.register_checker(NotChecker(linter)) linter.register_checker(RecommandationChecker(linter)) linter.register_checker(ElifChecker(linter)) |