Colby MchenryandClaude Opus 5.5
c58f0417c6
The Windows kernels read the `!` of every `try!` as a logical not, so `try! Message2(data: d)` became a call of `! Message2` that never resolves, and a call through a receiver lost it: `try! Settings.Defaults.load()` was a bare `load`. The cause is the grammar's C, not the walker. tree-sitter-swift 0.7.3's external scanner steps aside for the `!` of `try!` through a 64-bit mask whose entry is built as `1UL << FAKE_TRY_BANG`, bit 32. `unsigned long` is 32 bits on Windows and MSVC folds the overflowing shift to 0 (warning C4293), so the scanner never stepped aside: `try` parsed alone, then a prefix `!` on the callee. macOS and Linux have 64-bit longs, and clang's wasm32 build folds the shift to bit 31 (`_directive_endif`, valid at every expression start), so the wasm and the other kernels have always read `try!` right. The kernel now compiles the crate tarball's src/ itself, from codegraph-kernel/grammars/swift, with upstream 0.7.4's one-line fix (`1ULL`), as it already does for the Kotlin, Lua, Scala and Dart grammars. The patch and its provenance are in docs/grammars/tree-sitter-swift.patch and .md. parser.c is unchanged, so the node-kind and field tables still match the wasm, which is untouched. TortureTry.swift pins calls after try!, try? and try on both engines. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
3.3 KiB
tree-sitter-swift — provenance & the kernel's scanner patch
The kernel's vendored C (codegraph-kernel/grammars/swift/) is the src/ of
the alex-pinkus/tree-sitter-swift
(MIT) 0.7.3 crates.io tarball — the same files
src/extraction/wasm/tree-sitter-swift.wasm is built from (see
docs/design/swift-kernel-port-checklist.md §Grammar prep for why the
tarball and not the tag) — with the patch in tree-sitter-swift.patch
applied to src/scanner.c. The wasm is built from the unpatched tarball.
| file | upstream sha256 | patched sha256 |
|---|---|---|
src/parser.c |
d3edff6effe31b9a507f496577407987343b101b23eb7bee7a9b050e8ab5d27a |
unchanged |
src/scanner.c |
f3d6271d64f58c39eed544104a70ca2cf9ecbf80c5d900620f1afd38836542cb |
8acafef098ea4a52ebfc4cdf2fe26706113a22ac8ba2faf7d952755ff350cad6 |
What the patch fixes
The external scanner produces its own ! token, and steps aside for a !
written straight after try so the parser can read try!. It finds those
positions through a 64-bit mask whose entry for ! is built as
1UL << FAKE_TRY_BANG, bit 32. Where unsigned long is 32 bits that shift
overflows, and each compiler folds it differently:
- MSVC — both Windows kernels (
x86_64/aarch64-pc-windows-msvc) — folds it to 0 (warning C4293). The scanner never steps aside, sotry! Message2(data: d)parsed astryfollowed by a call of!Message2: the call was named! Message2and linked nothing, and a call through a type,try! Settings.Defaults.load(), lost its receiver. - clang for wasm32 (the wasm) folds it to bit 31,
_directive_endif, which is valid at every expression start — right aftertrytoo — so the wasm readstry!correctly. Its one other effect: a prefix!at an expression start is lexed by the parser's own lexer, which leaves an anonymous!token underbangwhere the scanner's token is hidden. No walker reads it. - macOS and Linux kernels (64-bit
unsigned long) were always correct.
The patch is upstream 0.7.4's one-line fix, 1ULL. Measured on 2026-10-09
over 1,172 Swift files (Alamofire, SDWebImage, protobuf, realm-swift,
swift-nio, vapor and six smaller projects): the patched native build parses
every error-free file to the same tree as the wasm, apart from that anonymous
!. The 8 files that differ have parse errors on both, and the kernel defers
a file with parse errors to the wasm. The unpatched MSVC build misparsed 157
error-free files, every one at a try!.
Rebuild
curl -sL https://crates.io/api/v1/crates/tree-sitter-swift/0.7.3/download -o ts-swift-0.7.3.crate
tar xzf ts-swift-0.7.3.crate && cd tree-sitter-swift-0.7.3
git apply /path/to/codegraph/docs/grammars/tree-sitter-swift.patch
cp src/parser.c src/scanner.c /path/to/codegraph/codegraph-kernel/grammars/swift/
cp src/tree_sitter/*.h /path/to/codegraph/codegraph-kernel/grammars/swift/tree_sitter/
Then rebuild the kernel (npm run build:kernel) and run
__tests__/kernel-grammar-parity.test.ts and scripts/kernel-parity.mjs --lang swift on a Swift repo: the wasm and the kernel must parse the same.
A bump to a release that carries the fix (0.7.4 or later) can drop the patch
and the vendored copy: pin the crate in codegraph-kernel/Cargo.toml again
and rebuild the wasm from the same tarball, together.