Optimize Cmake build slightly

[akx]

This follows up on #908 to make it do less work and simplify things some.

Since we don't actually link against the Python ABI, we only need to build on Python 3.10. CPython 3.10 and newer should happily accept a cp310 wheel:

$ docker run -it --platform=linux/amd64 python:3.12 sh -c 'pip debug --verbose | grep cp310'
[...]
  cp310-abi3-manylinux1_x86_64
  cp310-abi3-linux_x86_64

(#1010 discusses being able to force the wheel tag, so we could build on a newer, faster Python, but still get a cp310 wheel.)

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[akx]

cc @wkpark

[wkpark]

what about python3.9 or 3.8? pytorch nightly build still support python3.8/3.9 (https://download.pytorch.org/whl/nightly/torch/ Of course, I don't expect anyone still uses the old python3.8 for normal use.)

[akx]

Should be fine to lower the wheel tag to cp38 eventually!

[younesbelkada]

Thanks for the refactor ! Clean work !
I left few open questions - what do you think?

[younesbelkada]

can you elaborate on this change? Would this affect PRs from forks?

[akx]

Yes. I was running exploratory versions of this PR in my own fork, and the docs workflow wouldn't be necessary there.

[younesbelkada]

ok makes sense

[younesbelkada]

Hmm thinking about it, ideally I think we should add also another "old enough" python version such as 3.8 just to be sure
In the past we had some issues due to a wrong typehint (!) that broke transformers for python 3.8: #859 so I think adding it would circumvents such an issue being on main - what do you think?

[younesbelkada]

I just saw #1010 I think what you said makes sense, we could do the python=3.8 build in another PR - what do you think?

[akx]

We would add a follow-up step that tests the built libraries on all supported versions, but building the binaries (and wheel) only needs to occur on one version.

[younesbelkada]

Thanks again !

[younesbelkada]

cc @wkpark all good if we merge this?

[wkpark]

all good if we merge this?

Yes. looks good to me.

[Titus-von-Koeller]

Hey, I am not completely up to speed with everything, but I noticed that all the builds are kicked off even when I just add a documentation commit. That seems pretty wasteful.

Wouldn't it make sense to only trigger those workflows in cases where there was a change detected in the csrc directory and otherwise use the last cached one form a parent commit?

Not sure how easy/hard that is. Just sth that came to mind. It also doesn't need to be addressed right away, even if it's something we want to do.

[younesbelkada]

@Titus-von-Koeller great point, actually we can do that in a straightforward manner with GHA, let me open a quick PR and ping you

[younesbelkada]

@Titus-von-Koeller : #1015