This issue will end up touching more than just spack-config, but we need a central place for discussion.

Background

Currently, our repos.yaml configuration across build-ci and build-cd uses path-based ACCESS-NRI/spack-packages refs for spack v1. This was the convention for spack <v1.

This is fine, but spack now allows for updating and configuration of packages repositories using spack repo add/spack repo update, which means we can simplify our workflows.

This will require changes to build-ci (Dockerfile definition), build-cd (Prerelease creation of spack-packages repositories, and Release updating repositories), spack-config (updating repos.yaml) and spack-packages api-v2 branch (adding spack-repo-index.yaml).

Implementation Details

Unfortunately, we need to do a bit of pre-processing to determine if a ref is a commit, tag or branch, as spack repo update only supports --commit/--tag/--branch. We alreadydo a bit of this in build-cd (maybe it's time to make that it's own access-nri/actions?

For build-ci, we will probably not be able support both the old and new ways of spack-packages repo administration. Might need conditional RUN steps based on $SPACK_VERSION.