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pylint-dev
`too-few-public-methods` doesn't count dunder methods if inherited
Bug description
# pylint: disable=multiple-statements
from abc import ABC, abstractmethod
# All these classes have enough public methods according to pylint:
class Test:
def __init__(self) -> None: self._field = 1
def __getitem__(self, key: str) -> int: return self._field
def method1(self) -> None: print(self._field)
class MyABC1(ABC):
def __init__(self) -> None: self._field = 1
def getitem(self) -> int: return self._field
@abstractmethod
def method1(self) -> None: ...
class MyABC2(ABC):
def __init__(self) -> None: self._field = 1
def __getitem__(self, key: str) -> int: return self._field
@abstractmethod
def method1(self) -> None: ...
class Concrete1(MyABC1):
def method1(self) -> None: print("method1", self._field)
# but not this class
class Concrete2(MyABC2): # ← Too few public methods (1/2)
def method1(self) -> None: print("method1", self._field)
Configuration
No response
Command used
pylint main.py
Pylint output
************* Module main
main.py:26:0: R0903: Too few public methods (1/2) (too-few-public-methods)
Expected behavior
No warning about too few public methods
Pylint version
pylint 3.0.3
astroid 3.0.2
Python 3.11.6 (tags/v3.11.6:8b6ee5b, Oct 2 2023, 14:57:12) [MSC v.1935 64 bit (AMD64)]
OS / Environment
No response
Additional dependencies
No response
ABC1 has an additional public method "getitem". Is that what you find unexpected that pylint counted?
class Test has two public methods: __getitem__ and method1 (no warning, as expected)
class MyABC1 has two public methods: getitem and method1 (no warning, as expected)
class MyABC2 has two public methods: __getitem__ and method1 (no warning, as expected)
class Concrete1 implements the abstract method method1 of MyABC1 (no warning, as expected)
class Concrete2 implements the abstract method method1 of MyABC2 (warning, unexpected)
Ah, if the difference is just that too-few-public-methods thinks anything that starts with _ is private even if it's a dunder, then that's just #9420.
According to this logic ("too-few-public-methods thinks anything that starts with _ is private"), then there should be a warning for class Test - but there is not. (same for class MyABC2)
Apologies, I took #9420 at face value, but I cannot reproduce the behavior described there. Dunders besides __init__() are counted as public methods, so that explains why Test doesn't raise a warning.
Apparently, inherited dunders are not counted. If that's the part you'd like us to reconsider, I'm happy to reopen the issue for additional discussion.