Updating Spack Dependencies

Updating shared Spack dependencies in Polaris is part of the release workflow for supported machines. Compared with pixi dependency updates, Spack updates are heavier-weight because environments are shared and build times are often long.

Polaris now uses ./deploy.py backed by mache.deploy. For deployment behavior and templates, treat the mache docs as the source of truth:

• mache deploy user guide

• mache deploy developer guide

Workflow for Spack Dependency Changes

1. Create a version-update branch

   Use a branch like update-to-<version> (for example update-to-0.9.0-alpha.1).

2. Bump the Polaris version

   Update polaris/version.py to the target version and commit that change.

3. Update deployment inputs

   • Update pinned versions in deploy/pins.cfg:

     • [spack] for Spack-only pins

     • [all] for pins shared by pixi and Spack

   • Update Spack specs in deploy/spack.yaml.j2 as needed

   • Update deployment defaults/behavior in deploy/config.yaml.j2 only if deployment logic or paths need to change

4. Open a PR and track testing/deployment

   Include:

   • an Updates section listing changed versions and rationale

   • a Testing checklist by machine/compiler/MPI

   • a Deployment checklist for final shared deployment

5. Run test deployments before shared deployment

   Example:

   ./deploy.py --deploy-spack --spack-path <test_spack_path> \
       --compiler <compiler...> --mpi <mpi...> --recreate
   

6. Run required validation suites

   Follow the testing pages under updating_spack/testing/ before final deployment.

Adding a New Spack Package

To add a new package to Polaris Spack environments:

1. Add or update the package pin in deploy/pins.cfg ([spack] or [all]).

2. Add the corresponding spec in deploy/spack.yaml.j2 under library and/or software, whichever is appropriate.

3. If inclusion should be conditional, express that condition in Jinja2 template logic and document it in your PR.

4. Test on supported machine/compiler/MPI combinations.

Summary

• Update version and deployment inputs (deploy/pins.cfg, deploy/spack.yaml.j2).

• Validate with ./deploy.py test deployments.

• Coordinate final shared Spack deployment only after testing passes.

If deployment (pixi) dependencies also changed, follow Updating Deployment Dependencies.