feat(turbo-tasks-fetch): stub HTTP on wasm targets (#97585)
### What?
Reports HTTP as unsupported on wasm, in the shape of the `reqwest` API
`turbo-tasks-fetch` consumes,
so the crate compiles for wasm targets.
### Why?
`reqwest` cannot serve wasm here. Its only wasm backend targets
`wasm32-unknown-unknown` and is built
on the browser `fetch` API via `wasm-bindgen`. Under
`wasm32-wasip1-threads` that backend is still
selected (it keys off `target_arch = "wasm32"`), and it is both
API-incompatible (no
`ClientBuilder::connect_timeout`, no `ClientBuilder::timeout`, no
`Error::is_connect`) and — fatally —
**`!Send`**, which `turbo-tasks` requires of every task future. WASI
preview1 has no sockets to build a
native client on either.
### How?
This is deliberately **not** a client and does not pretend to be one:
building a client fails
immediately with a clear error, so no request is ever attempted, nothing
is retried, and no response is
ever produced. The remaining types exist only so the shared fetch code
type-checks, and the paths that
could never be reached say so rather than returning plausible dummy
values.
The error names the consequence and the alternatives, rather than
surfacing as a generic failure:
> HTTP requests are not supported in wasm builds of Next.js: this
platform has no HTTP client.
> Features that fetch at build time, such as `next/font/google`, cannot
be used here — self-host the
> assets, or use a platform with native Next.js binaries.
### Follow-up
Real support needs the **host** to provide HTTP: for wasm builds of the
Next.js bindings that means a
napi callback into the JS `fetch`, kept behind the existing
`FetchClientConfig` interface so callers are
unaffected. That is a separate PR by design — a `ThreadsafeFunction`
call from a wasi thread cannot be
validated until the wasm bindings can be instantiated, which is blocked
on the unreleased emnapi v2.
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Co-authored-by: vercel-fleet-prod[bot] <318278635+vercel-fleet-prod[bot]@users.noreply.github.com>
Co-authored-by: Tobias Koppers <1365881+sokra@users.noreply.github.com>
