feat(spm): SwiftPM package generation tooling

The scripts/spm toolchain that generates a SwiftPM Package.swift + xcodeproj
for React Native and community libraries, on top of the headers-spec header
layout (React.framework + ReactNativeHeaders, no VFS). Consumes
headers-compose.ensureHeadersLayout to compose the header artifacts; ships the
compose runtime + scripts/spm via the npm files allowlist.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: chrfalch

package.json

@@ -42,6 +42,7 @@
   },
   "workspaces": [
     "packages/*",
+    "packages/react-native-test-library/*",
     "private/*",
     "!private/helloworld"
   ],

packages/react-native/package.json

@@ -107,6 +107,12 @@
     "scripts/hermes/hermes-utils.js",
     "scripts/hermes/prepare-hermes-for-build.js",
     "scripts/ios-configure-glog.sh",
+    "scripts/ios-prebuild/headers-compose.js",
+    "scripts/ios-prebuild/headers-config.js",
+    "scripts/ios-prebuild/headers-inventory.js",
+    "scripts/ios-prebuild/headers-spec.js",
+    "scripts/ios-prebuild/headers.js",
+    "scripts/ios-prebuild/utils.js",
     "scripts/native_modules.rb",
     "scripts/node-binary.sh",
     "scripts/packager-reporter.js",
@@ -115,6 +121,8 @@
     "scripts/react_native_pods_utils/script_phases.sh",
     "scripts/react_native_pods.rb",
     "scripts/react-native-xcode.sh",
+    "scripts/setup-apple-spm.js",
+    "scripts/spm",
     "scripts/xcode/ccache-clang.sh",
     "scripts/xcode/ccache-clang++.sh",
     "scripts/xcode/ccache.conf",

packages/react-native/scripts/codegen/templates/Package.swift.spm-template

@@ -0,0 +1,80 @@
+// swift-tools-version: 6.0
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// AUTO-GENERATED by scripts/setup-apple-spm.js – do not edit manually.
+// This SPM-specific template replaces the CocoaPods codegen template
+// with xcframework configuration built in.
+
+import PackageDescription
+
+// React headers need NO search paths: React/react namespaces come from the
+// React binaryTarget (auto -F; headers + module map inside the framework),
+// every other namespace from the ReactNativeHeaders binaryTarget, and the
+// per-app generated headers from the ReactAppHeaders target below — all
+// auto-served by SPM through product/target dependencies.
+let headersDep: [Target.Dependency] = [
+    .product(name: "ReactNativeHeaders", package: "ReactNative"),
+    "ReactAppHeaders",
+]
+
+let package = Package(
+    name: "React-GeneratedCode",
+    platforms: [.iOS(.v15), .macCatalyst(SupportedPlatform.MacCatalystVersion.v13)],
+    products: [
+        .library(
+            name: "ReactCodegen",
+            targets: ["ReactCodegen"]),
+        .library(
+            name: "ReactAppDependencyProvider",
+            targets: ["ReactAppDependencyProvider"]),
+        .library(
+            name: "ReactAppHeaders",
+            targets: ["ReactAppHeaders"]),
+    ],
+    dependencies: [
+        .package(name: "ReactNative", path: "../../xcframeworks"),
+    ],
+    targets: [
+        .target(
+            name: "ReactCodegen",
+            dependencies: [
+                .product(name: "ReactNative", package: "ReactNative"),
+                .product(name: "ReactNativeDependencies", package: "ReactNative"),
+            ] + headersDep,
+            path: "ReactCodegen",
+            exclude: ["ReactCodegen.podspec"],
+            publicHeadersPath: ".",
+            cSettings: [.headerSearchPath("headers")],
+            cxxSettings: [.headerSearchPath("headers")],
+            linkerSettings: [
+                .linkedFramework("Foundation")
+            ]
+        ),
+        .target(
+            name: "ReactAppDependencyProvider",
+            dependencies: ["ReactCodegen"] + headersDep,
+            path: "ReactAppDependencyProvider",
+            exclude: ["ReactAppDependencyProvider.podspec"],
+            publicHeadersPath: ".",
+            cSettings: [.headerSearchPath(".."), .headerSearchPath("headers")],
+            cxxSettings: [.headerSearchPath(".."), .headerSearchPath("headers")],
+            linkerSettings: [
+                .linkedFramework("Foundation")
+            ]
+        ),
+        // The per-app generated-headers farm (built by spm sync), vended as a
+        // normal SPM headers target.
+        .target(
+            name: "ReactAppHeaders",
+            path: "ReactAppHeaders",
+            publicHeadersPath: "."
+        ),
+    ],
+    // React Native headers require C++20 (concepts, std::optional, etc.)
+    cxxLanguageStandard: .cxx20
+)