E1124:redundant-keyword-arg false positive on dataclass with kw_only=False that extends dataclass with kw_only=True

[DetachHead]

Bug description

import inspect
from dataclasses import dataclass


@dataclass(kw_only=True)
class Foo:
    a: int
    b: str


@dataclass(kw_only=False)
class Bar(Foo):
    c: int


print(inspect.signature(Bar.__init__))  # (self, c: int, *, a: int, b: str) -> None

a = Bar(1, a=2, b="")  # error: Argument 'a' passed by position and keyword in constructor call (E1124:redundant-keyword-arg)


print(a) # Bar(a=2, b='', c=1)

Configuration

No response

Command used

pylint asdf.py

Pylint output

************* Module asdf
asdf.py:18:4: E1124: Argument 'a' passed by position and keyword in constructor call (redundant-keyword-arg)

Expected behavior

no error

Pylint version

pylint 2.14.5
astroid 2.11.7
Python 3.10.6 (tags/v3.10.6:9c7b4bd, Aug  1 2022, 21:53:49) [MSC v.1932 64 bit (AMD64)]

OS / Environment

No response

Additional dependencies

No response

[jacobtylerwalls]

Thanks for the report. 👍🏻

I think this could be viewed as a sub-problem of #5767. Any fix for #5767 needs to handle this test case also. I'll cross-post there.

[DanielNoord]

Re-opening as I'd like to refocus #5767 to the KW_ONLY sentinel. Keeping this to track the issue of kw_only reordering the positional and keyword arguments needed for the dataclass constructor.

See also:

---

Happens with the kw_only parameter of dataclasses.field too:

"""Quick test to demonstrate pylint errors when using kw_only dataclass
fields."""
from dataclasses import dataclass, field

@dataclass
class Creature:
    """Defines a creature with one or more names (first names, middle names,
    last names, etc.)"""
    names: list[str] = field(kw_only=True)

@dataclass
class Human(Creature):
    """Defines a human who has a home address."""
    address: str

donna = Human('1858 Hidden Meadow Drive, East Grand Forks, ND 56721',
              names=['Donna', 'Jennings'])
print(donna)

Running pylint (2.12.2):

$ python -m pylint dc_kw_only.py 
************* Module dc_kw_only
dc_kw_only.py:16:8: E1124: Argument 'names' passed by position and keyword in constructor call (redundant-keyword-arg)
dc_kw_only.py:16:8: E1120: No value for argument 'address' in constructor call (no-value-for-parameter)

--------------------------------------------------------------------
Your code has been rated at -4.29/10

Running Python 3.10.2:

$ python dc_kw_only.py 
Human(names=['Donna', 'Jennings'], address='1858 Hidden Meadow Drive, East Grand Forks, ND 56721')

Originally posted by @Infernio in #5767 (comment)

[DanielNoord]

I posted a fix to astroid for this. Most issues with kw_only should be resolved with that PR.

[Infernio]

Finally got around to testing this. Unfortunately, I still get errors when using kw_only:

"""Docstring to quiet pylint."""
from dataclasses import dataclass, field

@dataclass
class ClassA:
    """Docstring to quiet pylint."""
    kw_field: str = field(kw_only=True)

@dataclass
class ClassB(ClassA):
    """Docstring to quiet pylint."""
    normal_field: int

print(ClassB(42, kw_field='Hello World'))

Runs fine on Python 3.10.7:

ClassB(kw_field='Hello World', normal_field=42)

But produces these errors when run through pylint (v2.15.4, with astroid v2.12.11):

************* Module demo
/tmp/demo.py:14:6: E1124: Argument 'kw_field' passed by position and keyword in constructor call (redundant-keyword-arg)
/tmp/demo.py:14:6: E1120: No value for argument 'normal_field' in constructor call (no-value-for-parameter)

Should I open a new issue for that?

[DanielNoord]

Can you open a new issue for this. Perhaps even in the astroid repo? That's where this ultimately should be fixed.

The issue is that we don't support kw_only in field (yet).