Re: rust: Crate Dependencies

[David Craven]

Hi Danny,

> How does rustc find the (Rust) dependencies when building a package in 
> cargo-build-system?

You should be able to override the default rust or cargo version by
passing #:rustc or/and #:cargo as arguments to the build-system. See
guix/build-system/cargo.scm.

> I read that there are actual Rust binary libraries, seldomly used, and 
> everything-included-only-as-source otherwise. How do I specify which it is?

By actual Rust binary library I assume you mean a library with a C ABI
that can be dynamically linked against, written in rust.

A library like that should or would contain a Cargo.lock file nailing
down all the crate versions required, making sure that the project can
be built using the same rustc and cargo versions.

With a Cargo.lock file present the only remaining issue is figuring
out whether it can be built with the rustc release or if it requires
features from beta/nightly.

I don't know a specific example of one, but I also read that it is
possible. I think that the cargo install should take care of
installing such a library, but I don't think it's implemented yet.

HTH!