ci: Reinstantiate CI files

[JesperDramsch]

This PR adds the following workflows:

• Public Label PR
• Conventional Commit PR titles
• PR labeller for convenience
• PR Pre-commit and testing

These depend on merge of:

• ci(pytest): Make installation skippable in pytest ecmwf-actions/reusable-workflows#144

[FussyDuck]

All committers have signed the CLA.

[MeraX]

Hi Jesper, I went through the yaml files. Most of them look uncontroversial to me. However, the reusable workflows aren't happy with their integration: reusable workflows should be referenced at the top-level jobs.*.uses' key, not within steps` https://github.com/ecmwf/anemoi-core/actions/runs/12710997502

[MeraX]

I'm trying to understand this line. As I understand it, it checks if there are changes between the commit pushed to develop (${{ github.sha }} and the previous HEAD of develop ${{ github.event.before }}. Subsequently, you install any of the three packages from the repository, if there were and changes and use PyPI otherwise.

Does this assume, that the previous HEAD of develop is always equal to the version on PyPI?

[JesperDramsch]

I tried not to make implicit assumptions here. I thought it makes most sense to try and see if there are any changes compared to the previous version on develop and not necessarily the released version.

[MeraX]

And another question: The Github Summary above reports "All checks have passed", even though the python-pull-request.yml is red. Do you consider making python-pull-request.yml mandatory once you PR is merged?

[MeraX]

Another thing that came to my mind: You are installing the three -core packages in individual steps. This might lead to a different resolution of package versions than installing them all at once: pip install -e graphs/[tests] -e training/[tests] -e models/[tests]. In particular, the current version would first install anemoi-graphs and anemoi-models from PyPI, as both are dependencies of ./training. In subsequent steps, both packages are overwritten with local versions. However, dependencies might still be installed in versions required in the PyPI packages and not as required by the local packages.

[JesperDramsch]

Hi Jesper, I went through the yaml files. Most of them look uncontroversial to me. However, the reusable workflows aren't happy with their integration: reusable workflows should be referenced at the top-level jobs.*.uses' key, not within steps` https://github.com/ecmwf/anemoi-core/actions/runs/12710997502

Oh that's a problem. Wasn't aware of that limitation.

[JesperDramsch]

This now runs the tests of changed code against:

1. Currently released code on PyPI (local-changes)

This mimics the way all other code in Anemoi currently runs, specifically against the released versions of other packages.

2. All other develops

This ensures that the code will stay up to date with coming changes on develop.

Current limitations

This can mean that if there are changes on develop that are not backwards compatible, but also aren't released yet, then some of the tests will fail.

I believe it's important to test both against released and current code on develop. so I added the label skip-ci-release-tests which can be applied to skip tests against pyPI releases, when we know there was a breaking change.