Sync unified docs with PR #22290 (in-process swift-syntax-rs parsing)

Co-authored-by: jketema <93738568+jketema@users.noreply.github.com>

Author: Copilot

unified/AGENTS.md

@@ -8,9 +8,10 @@ by Apple's swift-syntax rather than by tree-sitter.
 - To build the extractor, run `scripts/create-extractor-pack.sh`
 
 ## Swift Parser
-- Swift source is parsed by `swift-syntax-parse`, a small Swift/Rust binary in
-  `swift-syntax-rs` that wraps Apple's swift-syntax and emits the parse tree as
-  JSON. There is no grammar in this repository to edit.
+- Swift source is parsed by the `swift-syntax-rs` crate, which wraps Apple's
+  swift-syntax. The extractor calls `swift_syntax_rs::parse_to_json` in-process
+  to obtain the parse tree as JSON — there is no separate parser binary and no
+  grammar in this repository to edit.
 
 - `extractor/src/languages/swift/adapter.rs` converts that JSON into a yeast AST.
 
@@ -23,10 +24,9 @@ by Apple's swift-syntax rather than by tree-sitter.
 - The mapping from the parse tree to the target AST is found in `extractor/src/languages/swift/swift.rs`
 
 - To run tests for the parser and mapping, run `cargo test` in the `extractor`
-  directory. The tests need the `swift-syntax-parse` binary: point
-  `CODEQL_EXTRACTOR_UNIFIED_SWIFT_SYNTAX_PARSE` at it, or put it on `PATH`.
-  Corpus tests skip themselves when it cannot be found, so check for skips
-  before concluding a change is clean.
+  directory. Since the parser is linked in-process, this needs a working Swift
+  toolchain (so `swift-syntax-rs` can build). The tests can also be run under
+  Bazel via `bazel test //unified/extractor:all_tests`.
 
 - Extractor test cases are located at `extractor/tests/corpus/swift/*/*.swift`.
 

unified/swift-syntax-rs/README.md

@@ -132,27 +132,22 @@ The build does not depend on any particular version manager. You need:
   (currently `6.3.2`), used to build `swift-syntax` `603.0.2`. Install it any way
   you like — [swift.org](https://www.swift.org/install/) or
   [swiftly](https://www.swift.org/swiftly/) (which reads `.swift-version`), or a
-  system package. Just make sure `swift` is on your `PATH` (or point `build.rs`
-  at it with the `SWIFT` environment variable).
+  system package. Just make sure `swift` (and `swiftc`) are on your `PATH` —
+  `build.rs` invokes them directly and does not read any environment variable
+  to locate them.
 
 On Debian/Ubuntu the Swift runtime also needs `libncurses6` (and related libs)
 available on the system.
 
 ## Building & testing
 
-With `cargo` and `swift` on `PATH`:
+With `cargo` and `swift`/`swiftc` on `PATH`:
 
 ```sh
 cargo build
 cargo test
 ```
 
-If your `swift`/`swiftc` are not on `PATH`, point the build at them explicitly:
-
-```sh
-SWIFT=/path/to/swift SWIFTC=/path/to/swiftc cargo build
-```
-
 The first build compiles `swift-syntax` and can take several minutes.
 
 ## Building with Bazel (CI)
@@ -170,6 +165,10 @@ bazel test  //unified/swift-syntax-rs:swift_syntax_rs_test
 bazel run   //unified/swift-syntax-rs:swift-syntax-parse < some.swift
 ```
 
+The `swift-syntax-parse` binary is a debugging aid for looking at the raw
+swift-syntax JSON for some input; it is not shipped as part of the extractor
+pack, which links `swift-syntax-rs` directly instead.
+
 Requirements:
 
 - **`clang`** must be installed on the runner. `rules_swift` requires the Bazel
@@ -221,9 +220,9 @@ echo 'let x = 1' | cargo run --bin swift-syntax-parse
 The JSON tree is consumed by the CodeQL extractor, which converts it into a
 [`yeast::Ast`](../../shared/yeast) — the in-memory format its rewrite rules
 operate on. That adapter is a pure-Rust module living in the extractor
-(`unified/extractor/src/languages/swift/adapter.rs`), so the extractor never
-needs the Swift toolchain: it consumes the JSON produced out-of-process by this
-crate's `parse_to_json` / the `swift-syntax-parse` binary.
+(`unified/extractor/src/languages/swift/adapter.rs`). The extractor links
+`swift-syntax-rs` directly and consumes the JSON produced in-process by this
+crate's `parse_to_json`.
 
 ## Layout