Add CI jobs for checking and testing with no default features

[TimJentzsch]

Closes #32.

This PR adds two new jobs to the CI workflow to cargo check and cargo test with the --no-default-features flag. Currently this has mainly the effect of enabling no_std.

Notably these currently throw errors, which just highlights the need to include it in CI.

I'm not sure if I'm able to resolve these errors as I've never worked with no_std before, but I can certainly try :)

Side note: Why do we have both cargo check and cargo test jobs? Wouldn't cargo test always fail if cargo check fails?

TODO:

• Fix errors from migrating to [email protected]
• Fix errors from migrate to [email protected]
• Add CI checks/tests with --no-default-features --features alloc flags

⚠️ This is a breaking change! (I think) ⚠️

The fixes to the no-default-feature configuration is probably a breaking change.

[alice-i-cecile]

Notably these currently throw errors, which just highlights the need to include it in CI.

Yeah, I saw an existing bug on stretch about this, and I'm very happy to see CI fail here.

I'm not sure if I'm able to resolve these errors as I've never worked with no_std before, but I can certainly try :)

Thanks a ton. Let us know if you get stuck on anything.

Why do we have both cargo check and cargo test jobs? Wouldn't cargo test always fail if cargo check fails?

As a reviewer, it can be quite useful to tell at a glance the current state of a PR. Tests failing is less severe than compilation failures, which are less severe than things like clippy or formatting violations.

[TimJentzsch]

Four of these errors are caused by a dependency upgrade which was part of #1. The heapless crate has removed the heapless::consts module (changelog), which is used multiple times when the alloc and std features are disabled.

Should we first downgrade heapless again and properly upgrade in a new issue/PR or should this be fixed here?

[TimJentzsch]

Two more errors are also caused by a dependency upgrade, arrayvec doesn't have the Array trait anymore and changed the ArrayVec definition.

[alice-i-cecile]

I'd like to fix these issues here; the dependency upgrade was good for other reasons, and the fix should be self-contained.

[mockersf]

This PR adds two new jobs to the CI workflow to cargo check and cargo test with the --no-default-features flag. Currently this has mainly the effect of enabling no_std.

Could you also add those for --no-default-features --features alloc? It's the other feature that was tested by the original crate.

Side note: Why do we have both cargo check and cargo test jobs? Wouldn't cargo test always fail if cargo check fails?

I added the CI by copying this quickstart because I wanted something quick to setup to make sure tests would be kept green

[TimJentzsch]

This is now ready to review. Please take extra care while reviewing my fixes to the compile errors, I didn't really know what I was doing while converting the libraries to constant generics.

I think renaming the CI jobs also messed up the required checks, we might need to change the settings there (or change the names back).

[alice-i-cecile]

Looks great; that's a nice little application of const generics.

[TimJentzsch]

We probably need to bump a minor version for this, because it's probably a breaking change, right? Should I change the version in the Cargo.toml file or how is this usually handled?

[alice-i-cecile]

@TimJentzsch with respect to CI, I have two thoughts:

1. We should just remove the check steps. It's too noisy with this many jobs.
2. Once that's done, I can temporarily remove the need for CI to pass the renamed jobs, and then re-enable it for the new test tasks.