Am Samstag, dem 08.01.2022 um 18:57 +0100 schrieb Ludovic Courtès: > Hello! > > I’m opening this issue to discuss the possibility of changing > #:cargo-inputs and #:cargo-development-inputs to regular inputs, as a > followup to: > >   https://issues.guix.gnu.org/51845#10 > > I have a preliminary patch for ‘guix style’ and (guix build-system > cargo), but there’s a couple of stumbling blocks. > > First, after the hacky patch in the discussion above, I attempted to > turn #:cargo-inputs into ‘propagated-inputs’ (instead of ‘inputs’), > because that seemed to be somewhat more logical.  That cannot work > though, because then those packages would propagate to non-Rust > packages; for example, librsvg would depend on the “build output” of > rust-* instead of just depending on its source.  Anyway, I’m back to > ‘inputs’. > > Second, until now, these two things would have a different meaning: > >   #:cargo-inputs (list rust-cargo) > > vs. > >   (inputs (list rust-cargo)) > > In the latter case, the package depends on the build result of > ‘rust-cargo’; in the former case, the package depends on the source > of ‘rust-cargo’.  (See ‘rav1e’ for an example where this happens.) I suppose adding (package-source rust-cargo) to inputs to preserve the old meaning would not make much sense? If so, what about having a source output and using (list `(,rust-cargo "source") ...)? > Last, the change to ‘inputs’ would introduce a few cycles at the > level.  Those cycles vanish when we lower to bags and > derivations.  However, because of these cycles, things like ‘guix > refresh -l’ may not work; there might be other unexpected and > undesired side effects. What about making the change incrementally, so that outer layers can start adopting the new style while inner layers are being rebootstrapped. I also think it'd make sense to see how we could detect cycles through static analysis. > Some of these cycles could in theory be removed.  For instance, > ‘rust-cfg-if’ has an optional dependency on ‘rust-compiler-builtins’, > which leads to a cycle, but Cargo won’t let us actually remove that > dependency, even though it’s optional. Could we rewrite the toml file to tell Cargo it has no power over us? Could we define bootstrap mockups? > PS: I guess you already knew all this Efraim but I’m kinda >     (re)discovering it and now experiencing frustration firsthand.  > :-) Let's hope at least someone in our team has overcome Rust fatigue by the time the GCC frontend for it lands. Rust is an incredibly good language, all it needs is a reasonable compiler and build system. Cheers