access-esm1p6: add variant cice, generic-tracers and um

[harshula]

This PR increases flexibility by allowing the user to make the following choices:

1. cice = {4,5} (only cice4 has been tested)
2. generic-tracers = {True,False} (tested)
3. um = {access-esm1.5,access-esm1.6} (tested)

Closes #175

[harshula]

Testing in PR ACCESS-NRI/ACCESS-ESM1.6#15

[aidanheerdegen]

I was interested in how this is invoked. It looks like to use a different UM version it is necessary to specify it in two places, the spec and the depends

ACCESS-NRI/ACCESS-ESM1.6@4f990d7

spack:
    specs:
       - [email protected]_2024.12.0 um=access-esm1.6

   um7:
      require:
        - '@git.dev-access-esm1.6=access-esm1.6'

and when going from non-generic tracers to generic tracers it is also necessary to change the MOM5 branch

ACCESS-NRI/ACCESS-ESM1.6@3055fde

spack:
    specs:
       - [email protected]_2024.12.0

(Note above changed from [email protected]_2024.12.0 ~generic-tracers

   mom5:
      require:
        - '@git.dev_2024.08.14=access-esm1.6'

[harshula]

Your MOM5 question is answered in a comment:

    # TODO: Use the access-esm1.6 branch when it has been confirmed that
    #       MOM5 master supports building with generic tracers disabled.
    depends_on(
        "[email protected] type=ACCESS-CM",
        type="run",
        when="~generic-tracers",
    )
    depends_on(
        "[email protected] type=ACCESS-ESM",
        type="run",
        when="+generic-tracers",
    )

[harshula]

It looks like to use a different UM version it is necessary to specify it in two places, the spec and the depends

No. The um change is only required in the spack.yaml's packages section. For um, the variant in the SBR is there in case it is needed when not using a spack.yaml. It's almost like documentation.

e.g. ACCESS-NRI/ACCESS-ESM1.6#15 (comment)

[aidanheerdegen]

LGTM