➖ Only install typing_extensions for Python '<3.9'

[waketzheng]

Description

1. Only install typing_extensions for python '<3.10'

[svlandeg]

Thanks for the PR! This makes sense to me. Just a few questions/comments:

• I removed bumping the dependencies as this was causing conflicts and CI errors. Let's keep the PR atomic (dealing with one functionality only).
• Why < 3.10? Looking at _typing.py, it seems like typing_extensions is only used up to and including 3.8.
• What is a bit unfortunate is that many of our tutorial examples use from typing_extensions import Annotated. I worry that users won't be able to execute this code directly if they haven't got typing_extensions installed in their normal typer environment.

[svlandeg]

Hi @waketzheng, I see you're running into the same typing error we've encountered before: #1048 (comment)

Basically this happens when reimporting Literal. For now, it's find to leave that bit of duplicated code as-is.

[waketzheng]

many of our tutorial examples use from typing_extensions import Annotated

How about use from typer._typing import Annotated instead?

[svlandeg]

This PR looks good to me - it's a good idea not to install typing_extensions when we don't need it for Python 3.9 and above.

What is a bit unfortunate is that many of our tutorial examples use from typing_extensions import Annotated. I worry that users won't be able to execute this code directly if they haven't got typing_extensions installed in their normal typer environment.

How about use from typer._typing import Annotated instead?

As I see it, our options are:

• keep the examples as they are, and update them to from typing import Annotated when we drop Python 3.8
• update the examples to from typer._typing import Annotated as you suggest but this feels like adding unnecessary complexity to the tutorial examples (exposing what should be an implementation detail)
• we can have explicit Python 3.9+ examples for all tutorial examples, that import from typing instead. While I wouldn't mind working on this, it feels like a lot of wasted effort, especially if we plan on dropping Python 3.8 soon.

I'll leave this decision with Tiangolo 🙏

[github-actions]

📝 Docs preview for commit a3bdc86 at: https://58407af1.typertiangolo.pages.dev

[github-actions]

This pull request has a merge conflict that needs to be resolved.

[svlandeg]

We can close this one, as Python 3.8 is not supported anymore, and most edits here have become obsolete after PR 1464. We'll likely remove typing_extensions altogether.