BSK-E0142 error

dataclass_transform violations when the transform is applied via a base class

When a class is decorated with @dataclass_transform(...), subclasses that inherit from it behave like dataclasses with the transform's default settings overridable by keyword arguments on the class definition.

This rule detects: 1. A non-frozen subclass inheriting from a frozen transform-class (line 51). 2. Attribute assignment on a frozen transform-class instance (lines 63, 122). 3. Positional arguments to a kw_only transform-class constructor (lines 66, 82). 4. Comparison operators on transform-class instances that lack order=True (line 72).

from typing import dataclass_transform

@dataclass_transform(kw_only_default=True)
class ModelBase: ...

class Customer(ModelBase, frozen=True):
    id: int

c = Customer(3)           # E — kw_only requires keyword args
c.id = 4                  # E — frozen instance is immutable

How to handle it

Every rule is on by default — strict is the default, not a cage. You can dial BSK-E0142 down per-file or per-path from your editor or pyproject.toml, or fix the code so it type-checks. See the Type System rules and the complete diagnostic reference.

Canonical URL: https://www.basilisk-python.dev/errors/BSK-E0142