Drop Python 3.8 support

[abidlabs]

Given that Python 3.8 is EOL-ing in October, we can drop support for this. We can also consider ending support for 3.9 but that may be too aggressive for the 5.0 release

[pngwn]

We should drop 3.9 unless there is an exceptional reason not to. 3.10 contains some really nice typing features that would allow us to clean quite a few things up.

[abidlabs]

I'm not sure if its a good idea to drop support for Python 3.9 if there's still a year left and it might make Gradio 5 unusuable for many developers without having to install a new version of Python. It looks like ~10% of our users currently use Python 3.9 -- which is about the same % as Python 3.8, but at least that is being EOL'd.

As far as I can tell, there is only this place in the code place where we have to handle Python 3.9 or below explicitly is here:

gradio/gradio/route_utils.py

Line 823 in 94a1143

if sys.version_info < (3, 10):

[pngwn]

Hmm, i thought I responded to this.

While we don't explicitly handle versions elsewhere, there are definitely cases where we have multiple implementations to handle different versions. I definitely did this for the component docs. I didn't version sniff, but I did feature detection instead but it amounts to the same thing.

As an example, my image_slider component requires python 3.10, supporting lower version complicates the code without reason imo. I don't think asking people upgrade to a version of python that was released 3 years ago is a huge ask. As a comparison, we require node 18 in the client and that was released 1 year after python 3.10.

[abidlabs]

As a recent ex-Windows user, upgrading Python can be a major pain 😆 its not as simple as upgrading a library or even as simple as upgrading node versions. And it doesn't seem to be that rare either, a quick search on Spaces shows a decent number of Spaces that have set python_version to 3.9: https://huggingface.co/search/full-text?q=python_version&p=1

As an example, my image_slider component requires python 3.10, supporting lower version complicates the code without reason imo.

If supporting Python 3.9 does indeed make the code more difficult to maintain, I'd be fine with dropping support. But I'm pretty surprised to hear that. What does Python 3.9 not support for the image_slider component? Does adding from __future__ import annotations fix it?

[pngwn]

Does adding from future import annotations fix it?

No, i've always had this in an dropped 3.9 support later. I'll double check what the issue was.

[abidlabs]

results from an informal twitter poll just for fun: https://x.com/abidlabs/status/1810321004939612295

[pngwn]

34 ppl, kill it til its dead.