chore(build): switch to Poetry

[stegayet]

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Description

WIP

This is a proposal about switching from scattered build and requirements files to PEP-517 build system using poetry and poetry-core with pyproject.toml.
The work is not done yet, I'd like to get some feedback about the idea first before moving forward.

TODO

• Check that we have no regression in wheel content
• Check that dependencies version and extras are the same as before
• Update GH actions accordingly

[Nusnus]

Hey @stegayet , thank you for taking the lead on such proposal.
I had on my mind upgrading us to Poetry after 5.3 release, as the upcoming pytest-celery also uses poetry and I think it would benefit Celery as well.

That being said, it means that it will be interesting after the release which unfortunately is still delaying.
Also, I believe a proper upgrade should be on more repos and not just Celery.

@thedrow @auvipy - What do you think?

[stegayet]

I can do the same move for other repositories related to Celery 👍
We are not in a rush, this can definitely wait after 5.3 release.

Do you have an idea when 5.3 release is going to land ?

[auvipy]

Do you have an idea when 5.3 release is going to land ?

we plan to release it in this may

[Viicos]

What about keeping setuptools and just migrating to pyproject? Poetry can be tricky w.r.t. dependencies for libraries (see this article) and things might change with python-poetry/poetry#9135, meaning more work will have to be done once PEP 621 gets supported by Poetry.