flake8-typing-only-imports 0.1.6

A flake8 plugin that flags imports exclusively used for type annotations

flake8-typing-only-imports

flake8 plugin that flags imports which are exclusively used for type hinting.

Installation

pip install flake8-typing-only-imports

Codes

Code	Description
TYO100	Local import '{module}' only used for type hinting
TYO101	Remote import '{module}' only used for type hinting
TYO200	Annotation '{annotation}' needs to be wrapped in quotes to be treated as a forward reference

TYO101 is disabled by default.

Rationale

A common trade-off for annotating large code bases is you will end up with a large number of extra imports. In some cases, this can lead to import circularity problems.

One (good) solution, as proposed in PEP484 is to use forward references and type checking blocks, like this:

from typing import TYPE_CHECKING


if TYPE_CHECKING:
    from app.models import foo


def bar() -> 'foo':
    ...

At the same time, this is often easier said than done, because in larger code bases you can be dealing with hundreds of lines of imports for thousands of lines of code.

This plugin solves the issue of figuring out which imports to put inside your type-checking blocks 🚀

As a pre-commit hook

See pre-commit for instructions

Sample .pre-commit-config.yaml:

- repo: https://gitlab.com/pycqa/flake8
  rev: 3.7.8
  hooks:
  - id: flake8
    additional_dependencies: [flake8-typing-only-imports]