🔥 Drop support for Python 3.7

[kinuax]

CPython and click already dropped support for Python 3.7. I would propose to proceed accordingly here in order to benefit from:

• reducing the CI tests
• utilizing improved types without branching
• making available the syntax provided by 3.8:
  • assignment expressions
  • positional-only arguments
  • f-strings with =

3.7 occurrences are updated. Literal related branching is cleaned. _typing is updated and simplified. All local tests pass on 3.8-3.12 and Linux.

Context: #828

[github-actions]

📝 Docs preview for commit 18178cf at: https://63aa4de4.typertiangolo.pages.dev

[github-actions]

📝 Docs preview for commit 2e8fcdd at: https://27073bc3.typertiangolo.pages.dev

[github-actions]

📝 Docs preview for commit caf601e at: https://8c1c8efc.typertiangolo.pages.dev

[kinuax]

CI tests pass.

[svlandeg]

Thanks for the very thorough PR!

I'll have to ask @tiangolo what the term is he wants to drop Python 3.7 by.

Note - I'm also maintaining spaCy and there we just bumped the Typer pin to allow any v0.x. If Typer drops Python 3.7 which spaCy v3 still supports, we'll have to again restrict the upper bound for Typer there. And I can imagine spaCy not being the only repo that would run into this.

I think we'll want to drop 3.7 at some point, it's just a question of when :-)

[github-actions]

📝 Docs preview for commit 36c4439 at: https://0e84aba4.typertiangolo.pages.dev

[kinuax]

@svlandeg, thanks for reviewing the PR and for sharing your thoughts. 👍

I understand the concern about avoiding breaking dependent libraries.

Besides, I rechecked the click repo and I would like to inform (and also correct previous statements) that, although old, the specific change that drops 3.7 is not released yet (it was merged in main branch right after the latest release 8.1.7).
This means that, in my opinion, the consideration of dropping support in Typer would happen, at least, after a new click release takes place. So this PR is just a prep for that moment.

[tiangolo]

Thanks @kinuax! I want to keep support for Python 3.7 for a while. It's currently not being a problem (yet) so I prefer to delay this a bit.

I would also want to have some features and fixes in before dropping support, so that people stuck in 3.7 can benefit from them too.

[github-actions]

📝 Docs preview for commit 5facc11 at: https://b83f7230.typertiangolo.pages.dev

[kinuax]

@tiangolo, all right, I understand, thanks for clarifying.