diff options
Diffstat (limited to 'pylint/checkers/base.py')
| -rw-r--r-- | pylint/checkers/base.py | 59 |
1 files changed, 57 insertions, 2 deletions
diff --git a/pylint/checkers/base.py b/pylint/checkers/base.py index aeaa85379..cc7e90237 100644 --- a/pylint/checkers/base.py +++ b/pylint/checkers/base.py @@ -1661,7 +1661,6 @@ KNOWN_NAME_TYPES = { "inlinevar", } - HUMAN_READABLE_TYPES = { "module": "module", "const": "constant", @@ -1724,7 +1723,6 @@ def _create_naming_options(): class NameChecker(_BasicChecker): - msgs = { "C0102": ( 'Black listed name "%s"', @@ -2342,6 +2340,12 @@ class ComparisonChecker(_BasicChecker): "callable was made, which might suggest that some parenthesis were omitted, " "resulting in potential unwanted behaviour.", ), + "W0177": ( + "Comparison %s should be %s", + "nan-comparison", + "Used when an expression is compared to NaN" + "values like numpy.NaN and float('nan')", + ), } def _check_singleton_comparison( @@ -2402,6 +2406,52 @@ class ComparisonChecker(_BasicChecker): args=(f"'{root_node.as_string()}'", suggestion), ) + def _check_nan_comparison( + self, left_value, right_value, root_node, checking_for_absence: bool = False + ): + def _is_float_nan(node): + try: + if isinstance(node, astroid.Call) and len(node.args) == 1: + if ( + node.args[0].value.lower() == "nan" + and node.inferred()[0].pytype() == "builtins.float" + ): + return True + return False + except AttributeError: + return False + + def _is_numpy_nan(node): + if isinstance(node, astroid.Attribute) and node.attrname == "NaN": + if isinstance(node.expr, astroid.Name): + return node.expr.name in ("numpy", "nmp", "np") + return False + + def _is_nan(node) -> bool: + return _is_float_nan(node) or _is_numpy_nan(node) + + nan_left = _is_nan(left_value) + if not nan_left and not _is_nan(right_value): + return + + absence_text = "" + if checking_for_absence: + absence_text = "not " + if nan_left: + suggestion = "'{}math.isnan({})'".format( + absence_text, right_value.as_string() + ) + else: + suggestion = "'{}math.isnan({})'".format( + absence_text, left_value.as_string() + ) + + self.add_message( + "nan-comparison", + node=root_node, + args=("'{}'".format(root_node.as_string()), suggestion), + ) + def _check_literal_comparison(self, literal, node): """Check if we compare to a literal, which is usually what we do not want to do.""" nodes = (astroid.List, astroid.Tuple, astroid.Dict, astroid.Set) @@ -2495,6 +2545,11 @@ class ComparisonChecker(_BasicChecker): self._check_singleton_comparison( left, right, node, checking_for_absence=operator == "!=" ) + + if operator in ("==", "!=", "is", "is not"): + self._check_nan_comparison( + left, right, node, checking_for_absence=operator in ("!=", "is not") + ) if operator in ("is", "is not"): self._check_literal_comparison(right, node) |