Add initial C FFI bindings and error inspection

.github/workflows/rust.yml

@@ -262,6 +262,54 @@ jobs:
       - name: Test bytecode output
         run: cargo insta test -p insta-bytecode
 
+  ffi-tests:
+    name: Test FFI
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 60
+    needs:
+      - fmt
+      - typos
+      - clippy
+      - docs
+      - msrv
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: macos-latest
+          - os: ubuntu-26.04-arm
+          - os: ubuntu-latest
+    steps:
+      - name: Set environment
+        # Setting `RUSTFLAGS` overrides any flags set on .cargo/config.toml, so we need to
+        # set the target flags instead which are cumulative.
+        # Track https://github.com/rust-lang/cargo/issues/5376
+        run: |
+          target=$(rustc -vV | awk '/^host/ { print $2 }' | tr '[:lower:]' '[:upper:]' | tr '-' '_')
+          echo "CARGO_TARGET_${target}_RUSTFLAGS=$W_FLAGS" >> $GITHUB_ENV
+
+      - name: Checkout repository
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@631a55b12751854ce901bb631d5902ceb48146f7 # stable
+        with:
+          toolchain: stable
+
+      - name: Cache Cargo
+        uses: Swatinem/rust-cache@d1527c8f67ef9af357290475d4af4b0fab8f12e0 # v2.9.3
+
+      - name: Check generated C headers
+        run: |
+          cargo run --locked --profile ci -p diplomat-gen
+          git status --short --untracked-files=all -- ffi/boa_ffi/bindings/c/
+          test -z "$(git status --porcelain --untracked-files=all -- ffi/boa_ffi/bindings/c/)"
+
+      - name: Test C bindings
+        run: ./ffi/boa_ffi/tests/c/run.sh --ci
+
   cross-tests:
     name: Test
     runs-on: ubuntu-latest

Cargo.toml

@@ -58,6 +58,9 @@ bitflags = "2.13.2"
 clap = "4.6.7"
 colored = "3.1.1"
 cow-utils = "0.1.3"
+diplomat = { version = "0.16.0", default-features = false }
+diplomat-runtime = { version = ">= 0.15.2, < 0.17.0", default-features = false }
+diplomat-tool = { version = "0.16.0", default-features = false }
 fast-float2 = "0.2.4"
 hashbrown = "0.17.1"
 http = { version = "1.5.0" }

ffi/boa_ffi/.gitattributes

@@ -0,0 +1 @@
+bindings/** linguist-generated=true

ffi/boa_ffi/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "boa_ffi"
+description = "C bindings for the Boa JavaScript engine"
+publish = false
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+license.workspace = true
+repository.workspace = true
+rust-version.workspace = true
+
+[lib]
+crate-type = ["cdylib", "rlib"]
+
+[dependencies]
+boa_engine.workspace = true
+diplomat.workspace = true
+diplomat-runtime.workspace = true
+
+[lints]
+workspace = true