[feat] Support arbitrary Spack environment configuration

[jack-morrison]

reframe.core.buildsystems.Spack supports setting install_tree, but there are many other ways to configure a Spack environment. This proposal introduces support for setting arbitrary Spack environment configuration options. The implementation is nearly identical to how install_tree works.

As an example with the changes proposed here, one could set the following:
self.build_system.config_opts = ['concretizer:unify:false']

If the configuration option is not already present in the default spack.yaml, it is added. If the configuration option is present in the default spack.yaml, Spack overwrites them with the values given via spack config add.

[jenkins-cscs]

Can I test this patch?

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (9992947) 86.77% compared to head (e6d6ffc) 86.77%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #2819   +/-   ##
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  Coverage    86.77%   86.77%           
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  Files           60       60           
  Lines        11356    11361    +5     
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+ Hits          9854     9859    +5     
  Misses        1502     1502           

Impacted Files	Coverage Δ
reframe/core/buildsystems.py	96.18% <100.00%> (+0.05%)	⬆️

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[jack-morrison]

Assuming this is moving forwards and there're no name changes, etc, I'm happy to add docs changes for this PR as well. I'm wondering if config_opts is clear enough. I guess it does have the context of build_system, but only applies to Spack.

[vkarak]

Hi @jack-morrison, thanks for the PR, I think it makes sense.

I would also add a unit test in test_buildsystems.py that simply checks whether the spack config commands are emitted correctly (there are already some examples that you could use as a template for your unit test).

Regarding the docs, I think the documentation of the config_opts is sufficient. Perhaps, you can also add a comment about this in the Spack build system tutorial.

[jack-morrison]

I would also add a unit test in test_buildsystems.py that simply checks whether the spack config commands are emitted correctly (there are already some examples that you could use as a template for your unit test).

Addressed & passing locally for me via 48d5706

[jack-morrison]

Perhaps, you can also add a comment about this in the Spack build system tutorial.

Done via f9bc8e6

[vkarak]

Lgtm!

[vkarak]

ok to test