`cargo run` fails on WebAssembly target due to `CARGO_BUILD_TARGET` leaking into `rustc_codegen_spirv` build

[ghchinoy]

Summary

When running the standard cargo run development workflow, the build fails while compiling the web frontend (wasm-pack build ./wrapper --dev --target=web).

The failure occurs in the raster-nodes-shaders crate's build.rs script. The build script attempts to compile the rustc_codegen_spirv compiler backend, but the parent CARGO_BUILD_TARGET=wasm32-unknown-unknown environment variable is inherited by the inner cargo build. Because WebAssembly does not support dynamic libraries (dylib), the inner build fails.

Error Output

[INFO]: 🎯  Checking for the Wasm target...
[INFO]: 🌀  Compiling to Wasm...
   Compiling raster-nodes-shaders v0.1.0 (../Graphite/node-graph/nodes/raster/shaders)
error: failed to run custom build command for `raster-nodes-shaders v0.1.0 (../Graphite/node-graph/nodes/raster/shaders)`

Caused by:
  ...
  error: cannot produce dylib for `rustc_codegen_spirv v0.9.0 (https://github.com/Firestar99/rust-gpu-new?rev=c12f2161...#c12f2161)` as the target `wasm32-unknown-unknown` does not support these crate types

Steps to Reproduce

1. Clone the repository.
2. Ensure Node.js and Rust prerequisites are installed.
3. Run cargo run.
4. Observe the build crash when wasm-pack reaches raster-nodes-shaders.

Proposed Solution

The inner build initiated by cargo_gpu::Install inside node-graph/nodes/raster/shaders/build.rs needs to compile for the host OS, not the WebAssembly target.

Clearing the CARGO_BUILD_TARGET environment variable inside build.rs before it kicks off the cargo_gpu build resolves the issue and allows the compilation to succeed:

// node-graph/nodes/raster/shaders/build.rs

// Inside main():
unsafe { std::env::remove_var("CARGO_BUILD_TARGET"); }

// ... followed by the existing cargo_gpu::Install::from_shader_crate(...) logic

Environment

• OS: macOS 26.3.1 (Build 25D2128)
• Rust Version: rustc 1.92.0 (ded5c06cf 2025-12-08)
• Node.js: v22.21.1

🤖 AI disclosure

I used Gemini to help me understand the error message. This message and the fix are mine.