Add support for Python 3.12

[bdice]

Overview

Python 3.12 was released in October 2023. This issue tracks the work to add support for Python 3.12 to RAPIDS.

In #3, RAPIDS added support for Python 3.11, which was released in RAPIDS 24.04. The work to add Python 3.11 was heavily automated, and that could be done again for Python 3.12 to reduce the load on RAPIDS maintainers.

When should we drop Python 3.9?

Typically RAPIDS has kept the matrix of supported Python minor versions to 2 or 3 versions at a time. When adding Python 3.12, we should probably drop Python 3.9 as well.

SPEC 0 recommended dropping support for Python 3.9 in 2023Q4. Meanwhile, NEP 29 recommended dropping support for Python 3.9 as of Apr 05, 2024. Both of these deadlines have passed and several large Python libraries are now moving towards dropping Python 3.9, so it is probably reasonable to drop Python 3.9 around the same time that we add Python 3.12.

Tasks

Each section should be fully completed before moving to the next section.

CI images

• Add Python 3.12 builds of miniforge-cuda. Drop CUDA 11.2 and 11.5, add Python 3.11 and 3.12. miniforge-cuda#55
• Add Python 3.12 CI images (ci-conda, ci-wheel, citestwheel) Add Python 3.12 ci-imgs#137

CI workflows

Branch Strategy:

• Create a branch on shared-workflows called python-3.12
• Add Python 3.12 to the build matrix on the python-3.12 branch
• Add Python 3.12 to the test matrix on the python-3.12 branch
  • When adjusting the test matrix, be aware of total GPU resource consumption. Build jobs are CPU only but test jobs require GPUs. We want to keep our GPU consumption roughly the same (don't double the test matrix size), even if it gets a bit sparser in its coverage. We have some rough guidelines for how to decide on the matrix entries to include.

The above tasks are handled by: rapidsai/shared-workflows#213

RAPIDS repositories

First, create a checklist for tracking repository migration like the one we used for Python 3.11: #3 (comment)

For each repo,

1. Update .github/workflows/*.yaml to point to the python-3.12 branch of shared-workflows
2. Update dependencies.yaml to add support for Python 3.12.
3. Review any pyproject.toml files for necessary changes (classifiers, etc.)
4. Update docs (README, etc) that reference a single Python version to point to the latest (3.12).
5. Once CI passes, merge the PR.

Most of this is easy to automate with rapids-reviser, and we can copy from this previous migrator for Python 3.11: https://github.com/rapidsai/rapids-reviser/pull/11. We still need to manually review the PRs for missing pieces.

Once all repos are migrated to the python-3.12 branch, the migration is complete. We merge python-3.12 into the development branch on shared-workflows and then open follow-up PRs to each repo to reset the branches to that development branch. This "reset" is simple and should be automated with rapids-reviser.

Post-migration

• Update the ci-imgs repo's latest configuration to use Python 3.12. https://github.com/rapidsai/ci-imgs/blob/main/latest.yaml
  • The latest image is frequently used by CI jobs for building docs and testing notebooks. Be aware that issues may arise in those jobs.
• Update the docker repo's matrix.yaml and matrix-test.yaml
• Update the build matrix in pypi-wheel-scripts so that Python 3.12 wheels are checked: https://github.com/rapidsai/pypi-wheel-scripts/blob/fa1e8744c8ec961a5b5e38ae172ae9c8c51b4280/release/check-wheels.sh#L41-L45

[bdice]

Strategically, it may make sense to wait until we publish RAPIDS C++ wheels (#33). That will reduce the build time impact of adding another Python version -- and we already plan to keep the total amount of testing constant. I think it may be reasonable to target early RAPIDS 24.08 for adding Python 3.12 support.

[vyasr]

I think that's a good idea, may as well minimize the impact. Although I should note that we were limiting our Python versions to the same degree even pre-wheels (i.e. when we only had conda builds, so half as many total artifacts to output) so I doubt that the C++ wheels effort materially changes the calculus on how many Python versions we will support at a time.

[bdice]

Here is a proposal for the CI matrix I would recommend for Python 3.12: rapidsai/shared-workflows#213