wado-run-webgpu

The wado run-webgpu subcommand: it compiles a Wado program with wado and runs the component on a wasmtime host that serves wasi:webgpu.

Rules

• This crate is a workspace of its own and is excluded from the repository's, so that nothing at the repository root builds wgpu. Nothing here is built by cargo build at the repository root, mise run test, or the repository's clippy and fmt jobs. The test-webgpu CI job is what builds, lints and tests it, on every change that is not documentation.
• wasi-webgpu-wasmtime must build on the wasmtime the repository pins, since this crate shares wado-host's runner.
• A program behaves the same here as under wado run, which is the only reason to have both. wado_host::runner, guest and options hold what makes that so, and a divergence is a defect, not a variant.
• The tests set WADO as wado does (External Subcommands), so the tests and a real invocation reach the compiler through one path.
• Running needs a GPU adapter. wgpu finds none without a driver, and the host says so and exits rather than letting the guest see request-adapter answer none. On Linux mesa-vulkan-drivers supplies the lavapipe software adapter, which is what CI installs; macOS answers with Metal and Windows with D3D12.
• Dependencies live in this crate's own Cargo.toml, there being no workspace above it to hold them. The other Rust rules apply as written.