Flake type annotations plugin

The flake8 plugin checking for correct usage of the Python type annotations.

Use with flake8-annotations for even better results!

Installation

Plugin requires flake8 >3.0.0

pip install flake-type-annotations-plugin

Rules

TAN001

This rule disallows usage of Union and Optional type annotations and expects user to use the new | operator syntax.

Example:

# WRONG
from typing import Optional, Union

def func(arg: Optional[int]) -> Union[int, str]:  # violates TAN001
    return arg if arg is not None else "N/A"

# CORRECT
def func(arg: int | None) -> int | str:  # OK
    return arg if arg is not None else "N/A"

For Python versions <3.10 a top-level module import from __future__ import annotations must be included in order to use this syntax.

More can be read in PEP604.

TAN002

This rule disallows usage of type annotations where built-in types can be used.

Example:

# WRONG
from typing import List, Tuple

def func(arg: Tuple[int]) -> List[int]:  # violates TAN002
    return list(arg)

# CORRECT
def func(arg: tuple[int]) -> list[int]:  # OK
    return list(arg)

For Python versions <3.9 a top-level module import from __future__ import annotations must be included in order to use this syntax.

More can be read in PEP585.