Gate advanced features of citool to reduce compilation time

[Kobzol]

This reduces the duration of the citool step of the Calculate job matrix job, which is on the critical path for all CI executions, from ~1 minute to ~20s. It will also make it easier for us to add more stuff to citool in the future, because if we can gate it behind extended, it won't increase the duration of this job.

r? @ghost

[Kobzol]

r? @marcoieni

@rustbot ready

[marcoieni]

can you write a comment explaining why this is here?

[marcoieni]

I'm not sure if it's worth adding this complexity. I can imagine us easily introducing bugs because of this feature.

Aren't there other ways to speed up the compilation? E.g. cache dependencies or use a pre-compiled binary.

[Kobzol]

I'm not sure if it's worth adding this complexity. I can imagine us easily introducing bugs because of this feature.

Could you clarify what kind of bugs you have in mind? I can't imagine how this could cause any bugs.

Aren't there other ways to speed up the compilation? E.g. cache dependencies or use a pre-compiled binary.

A pre-compiled binary would IMO introduce too much implementation complexity, due to having to handle cache invalidations. An easy solution would be to use rust-cache. I was a bit vary of adding it to our CI, but as long as we would pin the hash and we only use it in the matrix computation step, I suppose that it should be fine. If you're ok with that, I will send a PR.

[marcoieni]

I prefer using the rust-cache action wrt to selecting features like this 👍

Could you clarify what kind of bugs you have in mind? I can't imagine how this could cause any bugs.

E.g. forget to add configuration flags around, which could cause compilation error. I have seen codebases that don't test all permutation of features that don't catch these errors, but probably in this CI would me more difficult.

Still I would prefer rust-cache to keep the code simpler 👍

[Kobzol]

E.g. forget to add configuration flags around, which could cause compilation error. I have seen codebases that don't test all permutation of features that don't catch these errors, but probably in this CI would me more difficult.

Right, I mean sure, there could be a compilation error, but that's not a bug =D We would compile the crate both with and without the single feature, so we would find out soon. But rust-cache should be simple.

[Kobzol]

Obsoleted by #139819.