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Fix a false positive for class attribute typed with Final #10712

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Fix a false positive for class attribute typed with Final #10712

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d5070be
[test] Add a regression test for #10711
Pierre-Sassoulas Nov 1, 2025
6e9c650
Generalize to final typing
Pierre-Sassoulas Nov 1, 2025
a6912ba
Add changelog
Pierre-Sassoulas Nov 1, 2025
dc85a9e
Better naming
Pierre-Sassoulas Nov 1, 2025
01a94d9
Better naming
Pierre-Sassoulas Nov 1, 2025
5fc003c
Fix behavior
jacobtylerwalls Nov 7, 2025
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4 changes: 4 additions & 0 deletions doc/whatsnew/fragments/10711.false_positive
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Original file line number Diff line number Diff line change
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Fix a false positive when an UPPER_CASED class attribute was raising an
``invalid-name`` when typed with ``Final``.

Closes #10711
4 changes: 3 additions & 1 deletion pylint/checkers/base/name_checker/checker.py
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Expand Up @@ -373,7 +373,9 @@ def leave_module(self, _: nodes.Module) -> None:
def visit_classdef(self, node: nodes.ClassDef) -> None:
self._check_name("class", node.name, node)
for attr, anodes in node.instance_attrs.items():
if not any(node.instance_attr_ancestors(attr)):
if not any(
node.instance_attr_ancestors(attr)
) and not utils.is_assign_name_annotated_with(anodes[0], "Final"):
self._check_name("attr", attr, anodes[0])

@utils.only_required_for_messages("disallowed-name", "invalid-name")
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26 changes: 26 additions & 0 deletions tests/functional/i/invalid/invalid_name/invalid_name_with_final_typing.py
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"""Regression test for https://github.com/pylint-dev/pylint/issues/10711."""

# pylint: disable=missing-class-docstring, missing-function-docstring

from dataclasses import dataclass
from typing import Final

module_snake_case_constant: Final[int] = 42 # [invalid-name]
MODULE_UPPER_CASE_CONSTANT: Final[int] = 42


def function() -> None:
function_snake_case_constant: Final[int] = 42
FUNCTION_UPPER_CASE_CONSTANT: Final[int] = 42 # [invalid-name]
print(function_snake_case_constant, FUNCTION_UPPER_CASE_CONSTANT)


@dataclass
class Class:
class_snake_case_constant: Final[int] = 42 # [invalid-name]
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@xiahualiu-txg xiahualiu-txg Nov 3, 2025

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This line should not raise [invalid-name], because Final attributes can still be re-assigned a new value that is different from the default value in __init__(). Final only protects the value after the instance is created.

Final is like const in C/C++. UPPER_CASE is like the marco which gets expanded during static interpretation of the code.

So UPPER_CASE is more immutable than Final.

So marking a dataclass attribute Final is not the sufficient condition for UPPER_CASE.
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@jacobtylerwalls jacobtylerwalls Nov 7, 2025

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Let's discuss that somewhere else. I don't want to make Final more special than it already is. The only thing we grok about Final is ...
CLASS_UPPER_CASE_CONSTANT: Final[int] = 42
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@xiahualiu-txg xiahualiu-txg Nov 3, 2025

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This line should be OK. Stacking them together should not raise any [invalid-name].
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@jacobtylerwalls jacobtylerwalls Nov 7, 2025

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... right here. (I agree with you)

Everything else in this file should be like Final doesn't even exist.
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@xiahualiu-txg xiahualiu-txg Nov 3, 2025

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I suggest adding a just UPPER_CASE attribute test case like:

CLASS_UPPER_CASE_ATTRIBUTE: int = 42

This line should not raise [invalid-name] here, because UPPER_CASE can be used alone to identify a static constant.

But later on if it gets re-assigned new value in the below method, then [invalid-name] should be raised there to ask for snake_case because it is no longer a constant.

def method(self) -> None:
method_snake_case_constant: Final[int] = 42
METHOD_UPPER_CASE_CONSTANT: Final[int] = 42 # [invalid-name]
print(method_snake_case_constant, METHOD_UPPER_CASE_CONSTANT)
4 changes: 4 additions & 0 deletions tests/functional/i/invalid/invalid_name/invalid_name_with_final_typing.txt
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invalid-name:8:0:8:26::"Constant name ""module_snake_case_constant"" doesn't conform to UPPER_CASE naming style":HIGH
invalid-name:14:4:14:32:function:"Variable name ""FUNCTION_UPPER_CASE_CONSTANT"" doesn't conform to snake_case naming style":HIGH
invalid-name:20:4:20:29:Class:"Class constant name ""class_snake_case_constant"" doesn't conform to UPPER_CASE naming style":HIGH
invalid-name:25:8:25:34:Class.method:"Variable name ""METHOD_UPPER_CASE_CONSTANT"" doesn't conform to snake_case naming style":HIGH