BridgeJS: replace the extraction logic with SwiftExtract

Package.swift

@@ -48,7 +48,8 @@ let package = Package(
     ],
     traits: [tracingTrait],
     dependencies: [
-        .package(url: "https://github.com/swiftlang/swift-syntax", "600.0.0"..<"604.0.0")
+        // SwiftExtract (BridgeJSTool's analysis layer) requires swift-syntax 603+.
+        .package(url: "https://github.com/swiftlang/swift-syntax", "603.0.0"..<"604.0.0")
     ],
     targets: [
         .target(
@@ -179,9 +180,31 @@ let package = Package(
             dependencies: ["BridgeJSTool"],
             path: "Plugins/BridgeJS/Sources/BridgeJSCommandPlugin"
         ),
+        .target(
+            name: "SwiftExtractConfigurationShared"
+        ),
+        .target(
+            name: "SwiftExtract",
+            dependencies: [
+                "SwiftExtractConfigurationShared",
+                .product(name: "SwiftBasicFormat", package: "swift-syntax"),
+                .product(name: "SwiftIfConfig", package: "swift-syntax"),
+                .product(name: "SwiftLexicalLookup", package: "swift-syntax"),
+                .product(name: "SwiftParser", package: "swift-syntax"),
+                .product(name: "SwiftSyntax", package: "swift-syntax"),
+                .product(name: "SwiftSyntaxBuilder", package: "swift-syntax"),
+            ],
+            resources: [
+                .process("Resources")
+            ],
+            swiftSettings: [
+                .swiftLanguageMode(.v5)
+            ]
+        ),
         .executableTarget(
             name: "BridgeJSTool",
             dependencies: [
+                "SwiftExtract",
                 .product(name: "SwiftParser", package: "swift-syntax"),
                 .product(name: "SwiftSyntax", package: "swift-syntax"),
                 .product(name: "SwiftBasicFormat", package: "swift-syntax"),

Plugins/BridgeJS/Package.swift

@@ -3,7 +3,8 @@
 import CompilerPluginSupport
 import PackageDescription
 
-let swiftSyntaxVersion = Context.environment["BRIDGEJS_OVERRIDE_SWIFT_SYNTAX_VERSION"] ?? "600.0.1"
+// SwiftExtract requires swift-syntax 603+ (SwiftLexicalLookup, SwiftIfConfig).
+let swiftSyntaxVersion = Context.environment["BRIDGEJS_OVERRIDE_SWIFT_SYNTAX_VERSION"] ?? "603.0.0"
 
 let package = Package(
     name: "BridgeJS",
@@ -14,6 +15,35 @@ let package = Package(
         .package(url: "https://github.com/apple/swift-argument-parser", from: "1.7.0"),
     ],
     targets: [
+        // SwiftExtract is swift-java's language-neutral Swift API extraction
+        // layer, symlinked from a sibling swift-java checkout while the
+        // BridgeJS adoption is developed against it.
+        .target(
+            name: "SwiftExtractConfigurationShared",
+            path: "Sources/SwiftExtractConfigurationShared"
+        ),
+        .target(
+            name: "SwiftExtract",
+            dependencies: [
+                "SwiftExtractConfigurationShared",
+                .product(name: "SwiftBasicFormat", package: "swift-syntax"),
+                .product(name: "SwiftIfConfig", package: "swift-syntax"),
+                .product(name: "SwiftLexicalLookup", package: "swift-syntax"),
+                .product(name: "SwiftParser", package: "swift-syntax"),
+                .product(name: "SwiftSyntax", package: "swift-syntax"),
+                .product(name: "SwiftSyntaxBuilder", package: "swift-syntax"),
+            ],
+            path: "Sources/SwiftExtract",
+            resources: [
+                // Checked-in build configuration for `#if` evaluation. In
+                // swift-java this file is generated by _StaticBuildConfigPlugin;
+                // here we ship a static default instead of carrying the plugin.
+                .process("Resources")
+            ],
+            swiftSettings: [
+                .swiftLanguageMode(.v5)
+            ]
+        ),
         .target(name: "BridgeJSBuildPlugin"),
         .executableTarget(
             name: "BridgeJSTool",
@@ -35,6 +65,7 @@ let package = Package(
             dependencies: [
                 "BridgeJSSkeleton",
                 "BridgeJSUtilities",
+                "SwiftExtract",
                 .product(name: "SwiftParser", package: "swift-syntax"),
                 .product(name: "SwiftSyntax", package: "swift-syntax"),
                 .product(name: "SwiftBasicFormat", package: "swift-syntax"),