Incorporate eval_type_backport to support evaluating PEP 585 and PEP 604 annotations on Python <3.10

[bswck]

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Example Code

from __future__ import annotations

import typer


def main(name: str | None = None) -> None:
    typer.echo(f"Hello, {name or 'world!'}")


__name__ == "__main__" and typer.run(main)

Description

Currently, typer doesn't support PEP 585 (on Python <3.9) and PEP 604 (on Python <3.10).

Pydantic adopted a backport which I worked on as well and it can be incorporated into typer, too.

The backport can be used from a third-party package called eval_type_backport (PyPI), maintained here.

Integrating with the backport might significantly reduce the need of using some deprecated/verbose typing components, such as typing.List (deprecated since 3.9, instead leverage PEP 585) or typing.Union (instead leverage PEP 604).

Operating System

Other

Operating System Details

All.

Typer Version

0.12.3

Python Version

3.8.19, 3.9.19

Additional Context

No response

[bswck]

@tiangolo