Allow overriding the nixci config attribute to evaluate

[ipetkov]

This allows invoking nixci .#alt-config which will evalute the alt-config attribute in the current flake. If not specified, it will fallback to using nixci as a default for backwards compatible behavior.

This is useful for situations where one might want to split up their nixci configs. For example, I have a project with a very large test suite (tests on both nixpkgs-unstable, as well as the latest release) and building all subflakes in one go makes the Github Action runners run out of disk space. But with this feature I can split up my configs in to separate "runs"

[srid]

Not sure about allowing/evaluating more than 1 (arbitrarily named) top-level flake output attr. We can change the schema to support multiple configs, at the cost of breaking backwards compatibility (which I'm fine with):

{
  outputs = _: {
    nixci = {
      default = { ... };
      alt-config = { ... };
    };
  };
}

Then, nixci . will use the "default" config, and nixci .#alt-config (for example) would use the other config. This structure is similar to packages, devShells, checks, too.

Wonder if there are other ways of solving your use case ...

[srid]

Something to think about: are there other requirements that will affect our decision regarding the new config schema? For example, #2.

[ipetkov]

A schema change might be the best way forward if it's in the cards, this was a simpler attempt to avoid introducing actual breaking changes!

[srid]

A schema change might be the best way forward if it's in the cards

Yup, let's go with that. I want to release 0.2 with this change.

[ipetkov]

Sounds good! Will close this as it's not going in the desired direction