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clavedelunaPierre-Sassoulas
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Pierre-Sassoulas
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Add bad-dunder-name extension checker (#7642)
With a 'good-dunder-name' option Co-authored-by: Pierre Sassoulas <[email protected]>
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-106
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10 files changed

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-106
lines changed

‎doc/data/messages/b/bad-dunder-name/bad.py‎

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class Apples:
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def _init_(self): # [bad-dunder-name]
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pass
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def __hello__(self): # [bad-dunder-name]
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print("hello")

‎doc/data/messages/b/bad-dunder-name/good.py‎

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class Apples:
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def __init__(self):
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pass
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def hello(self):
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print("hello")

‎doc/data/messages/b/bad-dunder-name/pylintrc‎

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[MAIN]
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load-plugins=pylint.extensions.dunder

‎doc/whatsnew/fragments/3038.new_check‎

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Added ``bad-dunder-name`` extension check, which flags bad or misspelled dunder methods.
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You can use the ``good-dunder-names`` option to allow specific dunder names.
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Closes #3038

‎pylint/checkers/dunder_methods.py‎

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from pylint.checkers import BaseChecker
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from pylint.checkers.utils import safe_infer
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from pylint.constants import DUNDER_METHODS
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from pylint.interfaces import HIGH
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if TYPE_CHECKING:
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from pylint.lint import PyLinter
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19-
DUNDER_METHODS: dict[tuple[int, int], dict[str, str]] = {
20-
(0, 0): {
21-
"__init__": "Instantiate class directly",
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"__del__": "Use del keyword",
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"__repr__": "Use repr built-in function",
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"__str__": "Use str built-in function",
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"__bytes__": "Use bytes built-in function",
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"__format__": "Use format built-in function, format string method, or f-string",
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"__lt__": "Use < operator",
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"__le__": "Use <= operator",
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"__eq__": "Use == operator",
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"__ne__": "Use != operator",
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"__gt__": "Use > operator",
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"__ge__": "Use >= operator",
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"__hash__": "Use hash built-in function",
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"__bool__": "Use bool built-in function",
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"__getattr__": "Access attribute directly or use getattr built-in function",
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"__getattribute__": "Access attribute directly or use getattr built-in function",
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"__setattr__": "Set attribute directly or use setattr built-in function",
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"__delattr__": "Use del keyword",
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"__dir__": "Use dir built-in function",
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"__get__": "Use get method",
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"__set__": "Use set method",
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"__delete__": "Use del keyword",
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"__instancecheck__": "Use isinstance built-in function",
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"__subclasscheck__": "Use issubclass built-in function",
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"__call__": "Invoke instance directly",
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"__len__": "Use len built-in function",
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"__length_hint__": "Use length_hint method",
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"__getitem__": "Access item via subscript",
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"__setitem__": "Set item via subscript",
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"__delitem__": "Use del keyword",
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"__iter__": "Use iter built-in function",
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"__next__": "Use next built-in function",
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"__reversed__": "Use reversed built-in function",
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"__contains__": "Use in keyword",
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"__add__": "Use + operator",
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"__sub__": "Use - operator",
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"__mul__": "Use * operator",
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"__matmul__": "Use @ operator",
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"__truediv__": "Use / operator",
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"__floordiv__": "Use // operator",
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"__mod__": "Use % operator",
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"__divmod__": "Use divmod built-in function",
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"__pow__": "Use ** operator or pow built-in function",
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"__lshift__": "Use << operator",
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"__rshift__": "Use >> operator",
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"__and__": "Use & operator",
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"__xor__": "Use ^ operator",
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"__or__": "Use | operator",
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"__radd__": "Use + operator",
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"__rsub__": "Use - operator",
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"__rmul__": "Use * operator",
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"__rmatmul__": "Use @ operator",
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"__rtruediv__": "Use / operator",
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"__rfloordiv__": "Use // operator",
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"__rmod__": "Use % operator",
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"__rdivmod__": "Use divmod built-in function",
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"__rpow__": "Use ** operator or pow built-in function",
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"__rlshift__": "Use << operator",
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"__rrshift__": "Use >> operator",
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"__rand__": "Use & operator",
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"__rxor__": "Use ^ operator",
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"__ror__": "Use | operator",
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"__iadd__": "Use += operator",
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"__isub__": "Use -= operator",
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"__imul__": "Use *= operator",
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"__imatmul__": "Use @= operator",
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"__itruediv__": "Use /= operator",
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"__ifloordiv__": "Use //= operator",
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"__imod__": "Use %= operator",
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"__ipow__": "Use **= operator",
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"__ilshift__": "Use <<= operator",
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"__irshift__": "Use >>= operator",
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"__iand__": "Use &= operator",
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"__ixor__": "Use ^= operator",
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"__ior__": "Use |= operator",
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"__neg__": "Multiply by -1 instead",
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"__pos__": "Multiply by +1 instead",
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"__abs__": "Use abs built-in function",
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"__invert__": "Use ~ operator",
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"__complex__": "Use complex built-in function",
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"__int__": "Use int built-in function",
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"__float__": "Use float built-in function",
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"__round__": "Use round built-in function",
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"__trunc__": "Use math.trunc function",
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"__floor__": "Use math.floor function",
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"__ceil__": "Use math.ceil function",
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"__enter__": "Invoke context manager directly",
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"__aenter__": "Invoke context manager directly",
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"__copy__": "Use copy.copy function",
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"__deepcopy__": "Use copy.deepcopy function",
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"__fspath__": "Use os.fspath function instead",
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},
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(3, 10): {
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"__aiter__": "Use aiter built-in function",
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"__anext__": "Use anext built-in function",
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},
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}
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class DunderCallChecker(BaseChecker):
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"""Check for unnecessary dunder method calls.
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Docs: https://docs.python.org/3/reference/datamodel.html#basic-customization
124-
We exclude __new__, __subclasses__, __init_subclass__, __set_name__,
125-
__class_getitem__, __missing__, __exit__, __await__,
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__aexit__, __getnewargs_ex__, __getnewargs__, __getstate__,
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__setstate__, __reduce__, __reduce_ex__,
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and __index__ (see https://github.com/PyCQA/pylint/issues/6795)
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We exclude names in list pylint.constants.EXTRA_DUNDER_METHODS such as
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__index__ (see https://github.com/PyCQA/pylint/issues/6795)
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since these either have no alternative method of being called or
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have a genuine use case for being called manually.
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‎pylint/constants.py‎

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"typing_extensions.Never",
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)
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)
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DUNDER_METHODS: dict[tuple[int, int], dict[str, str]] = {
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(0, 0): {
174+
"__init__": "Instantiate class directly",
175+
"__del__": "Use del keyword",
176+
"__repr__": "Use repr built-in function",
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"__str__": "Use str built-in function",
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"__bytes__": "Use bytes built-in function",
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"__format__": "Use format built-in function, format string method, or f-string",
180+
"__lt__": "Use < operator",
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"__le__": "Use <= operator",
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"__eq__": "Use == operator",
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"__ne__": "Use != operator",
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"__gt__": "Use > operator",
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"__ge__": "Use >= operator",
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"__hash__": "Use hash built-in function",
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"__bool__": "Use bool built-in function",
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"__getattr__": "Access attribute directly or use getattr built-in function",
189+
"__getattribute__": "Access attribute directly or use getattr built-in function",
190+
"__setattr__": "Set attribute directly or use setattr built-in function",
191+
"__delattr__": "Use del keyword",
192+
"__dir__": "Use dir built-in function",
193+
"__get__": "Use get method",
194+
"__set__": "Use set method",
195+
"__delete__": "Use del keyword",
196+
"__instancecheck__": "Use isinstance built-in function",
197+
"__subclasscheck__": "Use issubclass built-in function",
198+
"__call__": "Invoke instance directly",
199+
"__len__": "Use len built-in function",
200+
"__length_hint__": "Use length_hint method",
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"__getitem__": "Access item via subscript",
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"__setitem__": "Set item via subscript",
203+
"__delitem__": "Use del keyword",
204+
"__iter__": "Use iter built-in function",
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"__next__": "Use next built-in function",
206+
"__reversed__": "Use reversed built-in function",
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"__contains__": "Use in keyword",
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"__add__": "Use + operator",
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"__sub__": "Use - operator",
210+
"__mul__": "Use * operator",
211+
"__matmul__": "Use @ operator",
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"__truediv__": "Use / operator",
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"__floordiv__": "Use // operator",
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"__mod__": "Use % operator",
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"__divmod__": "Use divmod built-in function",
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"__pow__": "Use ** operator or pow built-in function",
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"__lshift__": "Use << operator",
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"__rshift__": "Use >> operator",
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"__and__": "Use & operator",
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"__xor__": "Use ^ operator",
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"__or__": "Use | operator",
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"__radd__": "Use + operator",
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"__rsub__": "Use - operator",
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"__rmul__": "Use * operator",
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"__rmatmul__": "Use @ operator",
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"__rtruediv__": "Use / operator",
227+
"__rfloordiv__": "Use // operator",
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"__rmod__": "Use % operator",
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"__rdivmod__": "Use divmod built-in function",
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"__rpow__": "Use ** operator or pow built-in function",
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"__rlshift__": "Use << operator",
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"__rrshift__": "Use >> operator",
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"__rand__": "Use & operator",
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"__rxor__": "Use ^ operator",
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"__ror__": "Use | operator",
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"__iadd__": "Use += operator",
237+
"__isub__": "Use -= operator",
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"__imul__": "Use *= operator",
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"__imatmul__": "Use @= operator",
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"__itruediv__": "Use /= operator",
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"__ifloordiv__": "Use //= operator",
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"__imod__": "Use %= operator",
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"__ipow__": "Use **= operator",
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"__ilshift__": "Use <<= operator",
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"__irshift__": "Use >>= operator",
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"__iand__": "Use &= operator",
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"__ixor__": "Use ^= operator",
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"__ior__": "Use |= operator",
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"__neg__": "Multiply by -1 instead",
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"__pos__": "Multiply by +1 instead",
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"__abs__": "Use abs built-in function",
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"__invert__": "Use ~ operator",
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"__complex__": "Use complex built-in function",
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"__int__": "Use int built-in function",
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"__float__": "Use float built-in function",
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"__round__": "Use round built-in function",
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"__trunc__": "Use math.trunc function",
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"__floor__": "Use math.floor function",
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"__ceil__": "Use math.ceil function",
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"__enter__": "Invoke context manager directly",
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"__aenter__": "Invoke context manager directly",
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"__copy__": "Use copy.copy function",
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"__deepcopy__": "Use copy.deepcopy function",
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"__fspath__": "Use os.fspath function instead",
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},
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(3, 10): {
267+
"__aiter__": "Use aiter built-in function",
268+
"__anext__": "Use anext built-in function",
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},
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}
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EXTRA_DUNDER_METHODS = [
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"__new__",
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"__subclasses__",
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"__init_subclass__",
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"__set_name__",
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"__class_getitem__",
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"__missing__",
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"__exit__",
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"__await__",
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"__aexit__",
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"__getnewargs_ex__",
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"__getnewargs__",
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"__getstate__",
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"__setstate__",
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"__reduce__",
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"__reduce_ex__",
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"__post_init__", # part of `dataclasses` module
289+
]
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DUNDER_PROPERTIES = [
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"__class__",
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"__dict__",
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"__doc__",
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"__format__",
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"__module__",
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"__sizeof__",
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"__subclasshook__",
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"__weakref__",
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]

‎pylint/extensions/dunder.py‎

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# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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# For details: https://github.com/PyCQA/pylint/blob/main/LICENSE
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# Copyright (c) https://github.com/PyCQA/pylint/blob/main/CONTRIBUTORS.txt
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5+
from __future__ import annotations
6+
7+
from typing import TYPE_CHECKING
8+
9+
from astroid import nodes
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11+
from pylint.checkers import BaseChecker
12+
from pylint.constants import DUNDER_METHODS, DUNDER_PROPERTIES, EXTRA_DUNDER_METHODS
13+
from pylint.interfaces import HIGH
14+
15+
if TYPE_CHECKING:
16+
from pylint.lint import PyLinter
17+
18+
19+
class DunderChecker(BaseChecker):
20+
"""Checks related to dunder methods."""
21+
22+
name = "dunder"
23+
priority = -1
24+
msgs = {
25+
"W3201": (
26+
"Bad or misspelled dunder method name %s.",
27+
"bad-dunder-name",
28+
"Used when a dunder method is misspelled or defined with a name "
29+
"not within the predefined list of dunder names.",
30+
),
31+
}
32+
options = (
33+
(
34+
"good-dunder-names",
35+
{
36+
"default": [],
37+
"type": "csv",
38+
"metavar": "<comma-separated names>",
39+
"help": "Good dunder names which should always be accepted.",
40+
},
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),
42+
)
43+
44+
def open(self) -> None:
45+
self._dunder_methods = (
46+
EXTRA_DUNDER_METHODS
47+
+ DUNDER_PROPERTIES
48+
+ self.linter.config.good_dunder_names
49+
)
50+
for since_vers, dunder_methods in DUNDER_METHODS.items():
51+
if since_vers <= self.linter.config.py_version:
52+
self._dunder_methods.extend(list(dunder_methods.keys()))
53+
54+
def visit_functiondef(self, node: nodes.FunctionDef) -> None:
55+
"""Check if known dunder method is misspelled or dunder name is not one
56+
of the pre-defined names.
57+
"""
58+
# ignore module-level functions
59+
if not node.is_method():
60+
return
61+
62+
# Detect something that could be a bad dunder method
63+
if (
64+
node.name.startswith("_")
65+
and node.name.endswith("_")
66+
and node.name not in self._dunder_methods
67+
):
68+
self.add_message(
69+
"bad-dunder-name",
70+
node=node,
71+
args=(node.name),
72+
confidence=HIGH,
73+
)
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76+
def register(linter: PyLinter) -> None:
77+
linter.register_checker(DunderChecker(linter))

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