sausage/spikes/s6-esbuild

S6: esbuild in WASI

This spike builds unpatched esbuild v0.27.7 for wasip1/wasm. Status: BLOCKED. The module bundles and renders, but both tested adapters trap. The test requires a bundle through both the module and the adapted component. Node executes each minified bundle with LinkeDOM and checks the rendered elements. The test also requires byte-identical output from native esbuild.

From the repository root:

nix develop -c nu spikes/s6-esbuild/build.nu
nix develop -c nu spikes/s6-esbuild/test.nu

Requirements: Go, Node, npm, Nushell, Git, curl, wasm-tools, and Wasmtime 49.0.2. The repository devshell supplies wasm-tools and Wasmtime. The recipe downloads the command adapter from the Wasmtime v49.0.2 release. Both the shared adapter and the v49.0.2 adapter fail with this Go build. The recipe stores sources, dependencies, binaries, and bundles in /tmp/s6-esbuild/. It fetches npm dependencies natively, not inside WASI.

The benchmark reports process wall times, not internal compiler times. It measures a first invocation and five repetitions with precompiled artifacts. The first invocation can use Wasmtime's existing compilation cache. The precompiled measurements exclude Cranelift compilation but include process startup and guest initialization. Only use the locally generated .cwasm files with --allow-precompiled.

The WASI preopen maps the fixture to / with --dir .::/. A relative guest preopen (--dir .) fails with Go's path resolution.

After the component blocker is resolved, probe optional CLI modes after the test:

nix develop -c nu spikes/s6-esbuild/limitations.nu

This fixture verifies a single entry point and no custom plugins. It does not verify a browser, the Sausage VFS, dependency installation in WASI, or TypeScript type checks. See .board/T6.report.md for measured limitations and results.

Rework 1

The clock probe succeeds with clock IDs 0 and 1 at precision 0. The Go probe also succeeds, even with additional initialization and allocation. Run both probes with:

nix develop -c nu spikes/s6-esbuild/diagnose.nu

The adapter assertion checks a state-memory sentinel, not clock support. An unstripped esbuild build also fails that assertion through fd_write. This evidence suggests memory corruption rather than an unsupported clock ID. It does not identify the writer.

eager-state.experimental.patch records an unverified adapter experiment. The patch reserves adapter state before the guest starts. Two attempts to build the adapter failed because of the local Rust target setup. The recipe does not apply this patch. The component bundle test and the precompiled benchmark remain blocked.