Maxime Devos schreef op za 02-04-2022 om 17:18 [+0200]:
>   * makes a few assumptions on the source layout (can be fixed
>     by using more info from Cargo.toml)

This has now been partially resolved.  It now looks in Cargo.toml to
determine where Rusts's equivalent of 'configure' (build.rs) is
located, and the Cargo.toml can now override the default src/lib.rs.

Some other improvements that weren't announced previously:

  * The code now automatically detects cycles and reports which
    packages are involved in the cycle.
  * --edition (cf. -std=c11/c99/...) is set appropriately, depending on
    Cargo.toml, fixing some build failures.
  * All default 'features' (in Cargo.toml) are now enabled by default.
  * Package definitions can request non-default features to be built
    anyway.

    A difference from cargo-build-system: features are set in the
    package of the rust crate, not the package using the rust crate.
  * build.rs is now run, which reduces the number of features that need
    to be set manually.
  * proc-macro crates are now named .so instead of .rlib, apparently
    naming them .rlib even though they aren't .rlibs confuses rustc
    or something.
  * #[deny(warnings)] (rust's equivalent of -Werrors) is now ignored
    (FWIW this is done by cargo as well).
  * Conversion from cargo-build-system to antioxidate-build-system is
    now automated by a recursive 'vitaminate/auto' procedure and some
    ad-hoc cycle breaking.

Some things that could perhaps be moved to (upstream) Guix:

  * Sometimes test and build.rs dependencies are listed in
    #:cargo-inputs and #:cargo-development-inputs (e.g.
    rust-quickcheck, rust-cc).  I deleted the test dependencies
    (because they contribute to cycles and for now running tests
    isn't supported anyways).
   
    Maybe they can be moved to #:cargo-development-inputs upstream
    (untested)?  Extending 'check-inputs-should-be-native' would also
    be nice too ...

  * There's a cycle between rust-backtrace-sys and rust-cc can be
    eliminated by deleting build.rs and tweaking Cargo.toml, at cost
    of losing some support for Android (which is not supported by Guix
    except in the sense that Linux is supported).

Greetings,
Maxime