luttik / auto-optional

Makes typed arguments Optional when the default argument is None

auto-optional

auto-optional: adds the Optional type-hint to arguments where the default value is None

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Documentation: auto-optional.daanluttik.nl

Source Code: github.com/luttik/auto-optional

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What does auto-optional do

The basic purpose of auto-optional is ensuring that whenever a default argument is None the type annotation is Optional.

For example:

def foo(bar: str = None):
    ...

Would turn into

from typing import Optional
def foo(bar: Optional[str] = None):
    ...

Why would you want this

• Easily modify external libraries that didn't pay attention to proper use of optional to improve mypy lintingf.
• Force consistency in your own code-base: Enforcing that None parameter implies an Optional type.
• Explicit is better than implicit — pep 20

In the media:

auto-optional was covered on PythonBytes #251

I love these little tools that you can run against your code that will just reformat them to be better.

— Michael Kennedy

Install

Install with pip install auto-optional.

Run

After installing you can run auto-optional using auto-optional [paths...] (if no path is provided it'll process the current working directory).

pre-commit

You can run auto-optional via pre-commit. Add the following text to your repositories .pre-commit-config.yaml:

repos:
- repo: https://github.com/luttik/auto-optional
  rev: v0.3.1 # The version of auto-optional to use
  hooks:
  - id: auto-optional

Things of note

Things that are handled well

• The alternatives to Optional are supported, that means both;
  • Union[X, None]
  • x | None (allowed since python 3.10+).
• Existing imports are reused.
  • import as and from typing import ... statements are properly handled.

Things that need improvement

For all these points you can leave a thumbs-up if you want it. Also, I welcome pull-requests for these issues.

• There is no exclude (for file patterns) option yet [#2]
• There is no ignore (for code lines) option yet [#3]
• Code is aways read and written as UTF-8 (which is accurate most of the time). [#4]
• There is no diff or check command yet for a dry-run or linting. [#5]

auto-optional's Issues

Add an exclude option.

Add an exclude option

Consider:

• Using glob-patterns
• Looking at other formatters and linters for the best patterns

Leave a 👍 if you want this

Error: Got unexpected extra arguments (list of files)

Hi @Luttik ,

I am trying to use it in an existing project and I am adding next config to my .pre-commit-config.yaml file.
The idea that I want to specify path to command so it checks src/ folder only
Here is an overview structure of project:

...
├── requirements-dev.in
├── requirements-dev.txt
├── requirements.in
├── requirements.txt
├── src
├── static
├── templates
├── tmp
...

This is config for auto-optional which I integrate into .pre-commit-config.yaml file

          ......
        - id: auto-optional
          name: auto-optional
          description: Adds the Optional type-hint to arguments where the default value is None
          entry: auto-optional src/
          language: python
          types: [python]
          ....

And I am getting next errors:

Error: Got unexpected extra arguments (src/asgi.py src/accounts/models/bill_blacklist_models.py src/hooks/models.py .... (continue list of files which should be proceeded)

---

How do I resolve it:

Added pass_filenames: false so in the end the config should be:

        - id: auto-optional
          name: auto-optional
          description: Adds the Optional type-hint to arguments where the default value is None
          entry: auto-optional src/
          language: python
          types: [python]
          pass_filenames: false

It takes longer time on the whole for verifying but this is a temp solution for that.

Add a `diff`, `dry-run` or `check` command for linting.

Add a diff, dry-run or check command for linting.

Preferably:

• --check

Leave a 👍 if you want this.

Support other file-formats than `UTF-8` for python code

Support other file-formats than UTF-8 for python code

Leave a 👍 if you want this

`Union[None, str]` should not become `Optional[Union[None, str]]`

Union[None, str] should not become Optional[Union[None, str]]

This does not make sense.

auto-optional==0.1.11
python 3.9.7

Add an in-line ignore option

Add an in-line ignore option.

Support:

• # noqa
• # auto-optional: ignore

Leave a 👍 if you want this