How to use pixi-managed rust to use zigbuild for cross-compilation

[amirhosseindavoody]

Problem Summary

I am building a rust code and using pixi to manage environment dependencies such as rust. I want to use zigbuild to cross compile to x86_64-unknown-linux-musl.

When attempting to build static musl binaries using cargo-zigbuild, the build failed with:

error[E0463]: can't find crate for `core`
  = note: the `x86_64-unknown-linux-musl` target may not be installed
  = help: consider downloading the target with `rustup target add x86_64-unknown-linux-musl`

Root Cause

The issue stems from using conda-forge managed Rust (via pixi) instead of rustup-managed Rust:

1. Conda-forge Rust only ships with the standard library for the host platform (x86_64-unknown-linux-gnu). It does not include pre-compiled standard libraries for cross-compilation targets like x86_64-unknown-linux-musl.

2. cargo-zigbuild provides Zig as a cross-compiler/linker (which includes musl libc), but it still requires the Rust standard library (core, std, alloc, etc.) pre-compiled for the target platform.

3. rustup target add is not available because conda-forge Rust doesn't use rustup - it's a standalone installation.

4. -Zbuild-std (which compiles the standard library from source) requires nightly Rust, but conda-forge only provides stable Rust.

Question

Is there anyway to use pixi-managed rust with zigbuild or the thing that I am trying to do is impossible right now.

[ismaildasci]

unfortunately conda-forge rust doesnt support cross compilation targets because it doesnt use rustup.

your options:

1. use rustup alongside pixi - install rust via rustup instead of pixi for rust itself, but keep other deps in pixi:

[dependencies]
# remove rust from pixi deps
cargo-zigbuild = "*"

then install rust with rustup separately:

curl --proto "=https" --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup target add x86_64-unknown-linux-musl

2. use build-std with nightly - add rust-nightly to pixi:

[dependencies]
rust-nightly = "*"

then:

cargo +nightly zigbuild -Z build-std --target x86_64-unknown-linux-musl

3. use cross instead of zigbuild - cross uses docker containers with pre-built targets:

cargo install cross
cross build --target x86_64-unknown-linux-musl

the fundamental issue is conda-forge rust is standalone binary without rustup toolchain management. for cross compilation rustup is better choice

[amirhosseindavoody]

Thanks for explaining the options. Having limited experience with rust, looks like option 2 to be optimal as it does enforce consistent environment managed by pixi yet, I can use zigbuild.

I don't know much about cross but I have seen people to praise zigbuild for cross compilation.