Support the wasm32-wasip3 target

.github/actions/setup/action.yml

@@ -4,7 +4,7 @@ description: Install system deps, Rust toolchain, WASI SDK, wasmtime, and config
 
 inputs:
   target:
-    description: Build target — "native" or "wasm32-wasip2"
+    description: 'Build target: "native", "wasm32-wasip2" or "wasm32-wasip3"'
     required: true
 
 runs:
@@ -33,8 +33,17 @@ runs:
       shell: bash
       run: rustup target add wasm32-wasip2
 
+    # The pinned toolchain ships no wasm32-wasip3 std, so the justfile builds that target with
+    # `cargo +nightly`. The pinned toolchain is still needed for the host-side test harnesses.
+    - name: Install nightly Rust toolchain with the wasm32-wasip3 target
+      if: inputs.target == 'wasm32-wasip3'
+      shell: bash
+      run: |
+        rustup toolchain install nightly --profile minimal --target wasm32-wasip3
+        rustc +nightly --version
+
     - name: Install WASI SDK
-      if: inputs.target == 'wasm32-wasip2'
+      if: inputs.target != 'native'
       shell: bash
       run: |
         sudo mkdir -p /opt/wasi-sdk
@@ -43,7 +52,7 @@ runs:
         echo "WASI_SDK_PATH=/opt/wasi-sdk" >> "$GITHUB_ENV"
 
     - name: Install wasmtime
-      if: inputs.target == 'wasm32-wasip2'
+      if: inputs.target != 'native'
       shell: bash
       run: |
         curl -sSf https://wasmtime.dev/install.sh | bash

.github/workflows/ci.yml

@@ -19,31 +19,35 @@ concurrency:
 env:
   CARGO_TERM_COLOR: always
   CARGO_INCREMENTAL: 0
-  WASI_SDK_VERSION: "33"
+  WASI_SDK_VERSION: "34"
   RUSTC_WRAPPER: sccache
   CCACHE: sccache
   # Bump to purge the sccache GHA cache.
   SCCACHE_GHA_VERSION: 1
 
 jobs:
   # ---------------------------------------------------------------------------
-  # Cargo tests: {native, wasm32-wasip2} × {debug+debugmozjs, release}
+  # Cargo tests: {native, wasm32-wasip2, wasm32-wasip3} × {debug+debugmozjs, release}
   # The wasm recipes also run the serve end-to-end suite (`just test-serve-wasm`).
   # ---------------------------------------------------------------------------
   test:
     name: Test (${{ matrix.target }}, ${{ matrix.profile }})
     strategy:
       fail-fast: false
       matrix:
-        target: [native, wasm32-wasip2]
+        target: [native, wasm32-wasip2, wasm32-wasip3]
         profile: [debug, release]
         include:
           - { target: native, profile: debug, recipe: test }
           - { target: native, profile: release, recipe: test-release }
           - { target: wasm32-wasip2, profile: debug, recipe: test-wasm }
           - { target: wasm32-wasip2, profile: release, recipe: test-wasm-release }
+          - { target: wasm32-wasip3, profile: debug, recipe: test-wasm }
+          - { target: wasm32-wasip3, profile: release, recipe: test-wasm-release }
     runs-on: ubuntu-latest
     env:
+      # Only the wasm recipes read this.
+      WASM_TARGET: ${{ matrix.target }}
       WASMTIME_BACKTRACE_DETAILS: '1'
       RUST_BACKTRACE: 'full'
     steps:
@@ -57,20 +61,21 @@ jobs:
         run: just ${{ matrix.recipe }}
 
       - name: Run example tests
-        if: matrix.target == 'wasm32-wasip2'
+        if: matrix.target != 'native'
         run: just ${{ matrix.recipe }} --examples
 
   # ---------------------------------------------------------------------------
-  # WPT suite: {native, wasm32-wasip2}
+  # WPT suite: {native, wasm32-wasip2, wasm32-wasip3}
   # ---------------------------------------------------------------------------
   wpt:
     name: WPT (${{ matrix.target }})
     strategy:
       fail-fast: false
       matrix:
-        target: [native, wasm32-wasip2]
+        target: [native, wasm32-wasip2, wasm32-wasip3]
     runs-on: ubuntu-latest
     env:
+      WASM_TARGET: ${{ matrix.target }}
       WASMTIME_BACKTRACE_DETAILS: '1'
       RUST_BACKTRACE: 'full'
     steps:
@@ -93,7 +98,7 @@ jobs:
       # The recipes build the runtime before running the harness.
       - name: Run WPT tests
         run: |
-          if [[ "${{ matrix.target }}" == "wasm32-wasip2" ]]; then
+          if [[ "${{ matrix.target }}" != "native" ]]; then
             just wpt-test-wasm -v
           else
             just wpt-test -v

Cargo.toml

@@ -47,8 +47,9 @@ starling-macro = { path = "crates/starling-macro" }
 tokio = { version = "1", features = ["rt", "time", "net", "io-util"] }
 url = "2.5.8"
 uuid = { version = "1.23", features = ["v4"] }
-wasip3 = { version = "0.8.0", features = ["http-compat"] }
-wit-bindgen = { version = "=0.61.0", features = ["macros"] }
+wasip3 = { version = "0.9.0", features = ["http-compat"] }
+# Must equal the `wit-bindgen` version `wasip3` depends on. See `starling/Cargo.toml`.
+wit-bindgen = { version = "=0.62.0", features = ["macros"] }
 wpt-support = { path = "crates/wpt-support" }
 
 # bindgen = { version = "0.72", default-features = false, features = [