cargo gpu seems to fail when called froma build script.

[Makogan]

In trying to invoke rustgpu from a build.rs scripts as follows:

 let result = std::process::Command::new("cargo")
        .arg("gpu")
        .arg("build")
        .arg("--force-overwrite-lockfiles-v4-to-v3")
        .arg("--auto-install-rust-toolchain")
        .arg("--output-dir")
        .arg(path)
        .current_dir(path)
        .output()
        .unwrap();

    // TODO(low) log shader compilation.
    println!("aaaaaaaaaa {}", String::from_utf8_lossy(&result.stdout));
    println!("aaaaaaaaaa {}", String::from_utf8_lossy(&result.stderr));
    println!("{}", path);

I encounter the following error:

  Caused by:
    process didn't exit successfully: `/home/makogan/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/rustc - --crate-name ___ --print=file-names -Zcodegen-backend=/home/makogan/.cache/rust-gpu/spirv-builder-cli/v0_9_0+nightly-2023-05-27/librustc_codegen_spirv.so -Zbinary-dep-depinfo -Csymbol-mangling-version=v0 '-Zcrate-attr=feature(register_tool)' '-Zcrate-attr=register_tool(rust_gpu)' -Coverflow-checks=off -Cdebug-assertions=off -Zinline-mir=off --target spirv-unknown-vulkan1.2 --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro --print=sysroot --print=split-debuginfo --print=crate-name --print=cfg` (exit status: 1)
    --- stderr
    warning: failed to connect to jobserver from environment variable `CARGO_MAKEFLAGS="-j --jobserver-fds=8,9 --jobserver-auth=8,9"`: cannot open file descriptor 8 from the jobserver environment variable value: Bad file descriptor (os error 9)
      |
      = note: the build environment is likely misconfigured

    error: error loading target specification: could not find specification for target "spirv-unknown-vulkan1.2"
      |
      = help: run `rustc --print target-list` for a list of built-in targets

  thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: BuildFailed', src/main.rs:152:38
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
  [2025-04-06T16:56:01Z ERROR cargo_gpu] build failed
  Error: build failed

To reproduce, attempt to compile any existing shader through a build.rs script

[tombh]

So you're saying that equivalent outside of build.rs does work? Something like:

cargo gpu build --force-overwrite-lockfiles-v4-to-v3 --auto-install-rust-toolchain --output-dir $path

Have you tried playing with the --shader-target argument?