Bug in python 3.8 when you use Annotated and annotations from __future__

[freddyaboulton]

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Example Code

from __future__ import annotations

import pathlib

import typer
from typing_extensions import Annotated

def main(config: Annotated[pathlib.Path, typer.Argument(help="foo")]):
    if config is None:
        print("No config file")
        raise typer.Abort()
    if config.is_file():
        text = config.read_text()
        print(f"Config file contents: {text}")
    elif config.is_dir():
        print("Config is a directory, will use all its config files")
    elif not config.exists():
        print("The config doesn't exist")


app = typer.Typer(help="Create and publish a new Gradio component")

app.command("main", help="Create a new component.")(main)


if __name__ == "__main__":
    app()

Description

Run the previous script in python 3.8. You will get a RunTimeError

If you run it in 3.9 or above it works. If you delete the from __future__ import annotations it will run successfully in 3.8. Also works if you do not use Annotated.

Operating System

macOS

Operating System Details

Mac OSX

Typer Version

0.9.0

Python Version

3.8.18

Additional Context

No response