Diff GitHub pull requests in the browser with diffr compiled to wasm

.aiderignore

@@ -1,2 +1,2 @@
-vendored_parsers/
+crates/diffr-core/vendored_parsers/
 sample_files/

.gitattributes

@@ -1,3 +1,3 @@
 # diffr is implemented in Rust; keep GitHub's language stats honest.
 sample_files/** linguist-vendored
-vendored_parsers/** linguist-vendored
+crates/diffr-core/vendored_parsers/** linguist-vendored

.github/workflows/test.yml

@@ -32,7 +32,7 @@
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
 
     - name: Install Rust toolchain
-      uses: dtolnay/rust-toolchain@1.85.0
+      uses: dtolnay/rust-toolchain@1.99.0
       with:
         targets: ${{ matrix.job.target }}
 
@@ -57,21 +57,46 @@
     steps:
       # v4.2.2
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-      - uses: dtolnay/rust-toolchain@1.85.0
+      - uses: dtolnay/rust-toolchain@1.99.0
         with:
           # The tests build every bundled plugin as a component.
           targets: wasm32-wasip2
       # Component loading is host behaviour, so it is tested once, natively,
       # rather than on every target the matrix above cross-compiles for.
       - run: cargo xtask test-plugins
 
+  build_core_wasm:
+    name: Build diffr-core for wasm32-unknown-unknown
+    runs-on: ubuntu-22.04
+    steps:
+      # v4.2.2
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+      - uses: dtolnay/rust-toolchain@1.99.0
+        with:
+          # The engine must keep building for the browser target; the
+          # grammars' archives need llvm-ar.
+          targets: wasm32-unknown-unknown
+          components: llvm-tools
+      # The engine and the diff session are one code path on every target:
+      # only loading a grammar differs in the browser. What a target lacks
+      # (git, threads, Wasmtime, a clock) comes from the caller instead.
+      - name: Check that only the grammar loader is gated by target
+        run: |
+          gated=$(git grep -l target_family -- crates/diffr-core/src ':!crates/diffr-core/src/parse/tree_sitter_parser.rs' || true)
+          if [ -n "$gated" ]; then
+            echo "target_family gates outside parse/tree_sitter_parser.rs:"
+            echo "$gated"
+            exit 1
+          fi
+      - run: cargo xtask build-core-wasm
+
   test_mime_db:
     name: Test with MIME database
     runs-on: ubuntu-22.04
     steps:
       # v4.2.2
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-      - uses: dtolnay/rust-toolchain@1.85.0
+      - uses: dtolnay/rust-toolchain@1.99.0
       # This runs tests that rely on the MIME database being present.
       - run: cargo test -- --ignored
 
@@ -90,7 +115,7 @@
     steps:
       # v4.2.2
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-      - uses: dtolnay/rust-toolchain@1.85.0
+      - uses: dtolnay/rust-toolchain@1.99.0
       - run: cargo fmt --all -- --check
 
   actionlint:
@@ -129,9 +154,9 @@
       - uses: oven-sh/setup-bun@0c5077e51419868618aeaa5fe8019c62421857d6 # v2.2.0
         with:
           bun-version: 1.3.10
-      - uses: dtolnay/rust-toolchain@1.85.0
+      - uses: dtolnay/rust-toolchain@1.99.0
       - run: cargo build --locked
-      - run: cargo test --locked --features all-languages --bin diffr --test cli
+      - run: cargo test --locked --features all-languages --lib --bin diffr --test cli
       - working-directory: diffr-ts
         run: |
           bun install --frozen-lockfile

.typos.toml

@@ -1,7 +1,7 @@
 [files]
 extend-exclude = [
-  "vendored_parsers/", "sample_files/",
-  "src/tags/linguist/",
+  "crates/diffr-core/vendored_parsers/", "sample_files/",
+  "crates/diffr-core/src/tags/linguist/",
   "demo_files/",
   # Git index lines carry blob hashes that can spell words.
   "examples/review/real/*/change.patch",