Make alloc optional

[mkj]

This puts all uses of alloc behind cfg, allowing to run on no_std platforms without alloc. It also sets default-features=false for getrandom and zeroize dependencies, getrandom's std or js are already set by features.

This patch is a bit cluttered with the #[cfg]. An alternative would be to move most of libs.rs to a new normal.rs module and then toplevel lib.rs could export those by default, or only bcrypt.rs modules for the no-alloc case. It'd be a bigger change, let me know what you'd prefer.

[mkj]

The plain bcrypt() function works OK, I'm using it on a rp2040 microcontroller. Storing the raw hash/salt rather than the formatted version.

https://github.com/mkj/sunset/blob/a5a62f418900e8d220c29303323cbbd67530b103/embassy/demos/common/src/config.rs#L249

[Keats]

Can you add test setup in CI for running it without that feature enabled?

[mkj]

I've added a small bare metal Arm example to test it. That also checks that getrandom crate isn't getting pulled in since that won't work on a bare metal platforms (without extra getrandom customisation, anyway).

[Keats]

Looks like we need to bump the Rust version to 1.60

[mkj]

Ah yeah, looks like it's unrelated to this PR, just log crate itself updated? https://old.reddit.com/r/rust/comments/12jepss/log_is_going_to_bump_msrv_to_160/

(A pity github delete the logs from the last successful build to compare)

[tarcieri]

FWIW, checking in Cargo.lock can prevent these sorts of random, unrelated regressions.

Related: https://github.com/rust-lang/cargo/issues/9930#issuecomment-1515427835

[Keats]

I kind of like knowing about those tbh

[tarcieri]

@Keats if you enable Dependabot you'll receive PRs to bump Cargo.lock which will show you immediately that dependency updates are breaking MSRV, while keeping PRs green and free of unexpected breakages or having to deal with MSRV bumps

[Keats]

I think the current PR is fine, the only thing missing is a little text in the README to explain what's available if alloc is not enabled

[mkj]

That's a good suggestion. I've added a note to the README now.

[Keats]

Thanks, it's available in 0.15.0