feat: add macOS and visionOS support to SPM build system

- Add macOS and visionOS platforms to ios-prebuild CLI and type definitions
- Build Hermes from source at the merge base with facebook/react-native
  when no prebuilt artifacts are available (main branch / 1000.0.0)
- Fix host hermesc cmake build by setting CMAKE_OSX_DEPLOYMENT_TARGET to
  prevent -Werror=unguarded-availability-new failures in LLVM config checks
- Map ReactNativeDependencies version to upstream RN via peerDependencies,
  with fallback to latest stable release for main branch
- Conditionally include macOS-specific platform view sources in Package.swift
  using #if os(macOS) to avoid compiling macOS C++ on iOS/visionOS
- Allow skipping ReactNativeDependencies download via SKIP_REACT_NATIVE_DEPENDENCIES
  env var for CI jobs that only build Hermes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Saadnajmi

packages/react-native/Package.swift

@@ -246,7 +246,7 @@ let reactJsErrorHandler = RNTarget(
 let reactGraphicsApple = RNTarget(
   name: .reactGraphicsApple,
   path: "ReactCommon/react/renderer/graphics/platform/ios",
-  linkedFrameworks: ["UIKit", "CoreGraphics"],
+  linkedFrameworks: ["CoreGraphics"],
   dependencies: [.reactDebug, .jsi, .reactUtils, .reactNativeDependencies]
 )
 
@@ -360,12 +360,21 @@ let reactCore = RNTarget(
     "ReactCommon/react/runtime/platform/ios", // explicit header search path to break circular dependency. RCTHost imports `RCTDefines.h` in ReactCore, ReacCore needs to import RCTHost
   ],
   linkedFrameworks: ["CoreServices"],
-  excludedPaths: ["Fabric", "Tests", "Resources", "Runtime/RCTJscInstanceFactory.mm", "I18n/strings", "CxxBridge/JSCExecutorFactory.mm", "CoreModules"],
-  dependencies: [.reactNativeDependencies, .reactCxxReact, .reactPerfLogger, .jsi, .reactJsiExecutor, .reactUtils, .reactFeatureFlags, .reactRuntimeScheduler, .yoga, .reactJsInspector, .reactJsiTooling, .rctDeprecation, .reactCoreRCTWebsocket, .reactRCTImage, .reactTurboModuleCore, .reactRCTText, .reactRCTBlob, .reactRCTAnimation, .reactRCTNetwork, .reactFabric, .hermesPrebuilt],
+  excludedPaths: ["Fabric", "Tests", "Resources", "Runtime/RCTJscInstanceFactory.mm", "I18n/strings", "CxxBridge/JSCExecutorFactory.mm", "CoreModules", "RCTUIKit"],
+  dependencies: [.reactNativeDependencies, .reactCxxReact, .reactPerfLogger, .jsi, .reactJsiExecutor, .reactUtils, .reactFeatureFlags, .reactRuntimeScheduler, .yoga, .reactJsInspector, .reactJsiTooling, .rctDeprecation, .reactCoreRCTWebsocket, .reactRCTImage, .reactTurboModuleCore, .reactRCTText, .reactRCTBlob, .reactRCTAnimation, .reactRCTNetwork, .reactFabric, .hermesPrebuilt, .reactRCTUIKit],
   sources: [".", "Runtime/RCTHermesInstanceFactory.mm"]
 )
 
 /// React-Fabric.podspec
+// [macOS: conditionally include macOS-specific platform sources for view components
+#if os(macOS)
+let reactFabricViewPlatformSources = ["components/view/platform/macos"]
+let reactFabricViewPlatformExcludes = ["components/view/platform/cxx"]
+#else
+let reactFabricViewPlatformSources = ["components/view/platform/cxx"]
+let reactFabricViewPlatformExcludes = ["components/view/platform/macos"]
+#endif
+// macOS]
 let reactFabric = RNTarget(
   name: .reactFabric,
   path: "ReactCommon/react/renderer",
@@ -376,7 +385,6 @@ let reactFabric = RNTarget(
     "components/view/tests",
     "components/view/platform/android",
     "components/view/platform/windows",
-    "components/view/platform/macos",
     "components/scrollview/tests",
     "components/scrollview/platform/android",
     "mounting/tests",
@@ -399,9 +407,9 @@ let reactFabric = RNTarget(
     "components/unimplementedview",
     "components/virtualview",
     "components/root/tests",
-  ],
+  ] + reactFabricViewPlatformExcludes, // [macOS]
   dependencies: [.reactNativeDependencies, .reactJsiExecutor, .rctTypesafety, .reactTurboModuleCore, .jsi, .logger, .reactDebug, .reactFeatureFlags, .reactUtils, .reactRuntimeScheduler, .reactCxxReact, .reactRendererDebug, .reactGraphics, .yoga],
-  sources: ["animations", "attributedstring", "core", "componentregistry", "componentregistry/native", "components/root", "components/view", "components/view/platform/cxx", "components/scrollview", "components/scrollview/platform/cxx", "components/legacyviewmanagerinterop", "dom", "scheduler", "mounting", "observers/events", "telemetry", "consistency", "leakchecker", "uimanager", "uimanager/consistency"]
+  sources: ["animations", "attributedstring", "core", "componentregistry", "componentregistry/native", "components/root", "components/view", "components/scrollview", "components/scrollview/platform/cxx", "components/legacyviewmanagerinterop", "dom", "scheduler", "mounting", "observers/events", "telemetry", "consistency", "leakchecker", "uimanager", "uimanager/consistency"] + reactFabricViewPlatformSources // [macOS]
 )
 
 /// React-RCTFabric.podspec
@@ -420,16 +428,13 @@ let reactFabricComponents = RNTarget(
     "components/modal/platform/cxx",
     "components/view/platform/android",
     "components/view/platform/windows",
-    "components/view/platform/macos",
     "components/textinput/platform/android",
     "components/text/platform/android",
-    "components/textinput/platform/macos",
     "components/text/tests",
     "textlayoutmanager/tests",
     "textlayoutmanager/platform/android",
     "textlayoutmanager/platform/cxx",
     "textlayoutmanager/platform/windows",
-    "textlayoutmanager/platform/macos",
     "conponents/rncore", // this was the old folder where RN Core Components were generated. If you ran codegen in the past, you might have some files in it that might make the build fail.
   ],
   dependencies: [.reactNativeDependencies, .reactCore, .reactJsiExecutor, .reactTurboModuleCore, .jsi, .logger, .reactDebug, .reactFeatureFlags, .reactUtils, .reactRuntimeScheduler, .reactCxxReact, .yoga, .reactRendererDebug, .reactGraphics, .reactFabric, .reactTurboModuleBridging],
@@ -524,6 +529,16 @@ let reactSettings = RNTarget(
   dependencies: [.reactTurboModuleCore, .yoga]
 )
 
+// [macOS
+/// React-RCTUIKit.podspec
+/// UIKit/AppKit compatibility layer for React Native macOS.
+let reactRCTUIKit = RNTarget(
+  name: .reactRCTUIKit,
+  path: "React/RCTUIKit",
+  excludedPaths: ["README.md"]
+)
+// macOS]
+
 // MARK: Target list
 let targets = [
   reactDebug,
@@ -581,13 +596,14 @@ let targets = [
   reactAppDelegate,
   reactSettings,
   reactRuntimeExecutor,
+  reactRCTUIKit, // [macOS]
 ]
 
 // MARK: Package object
 
 let package = Package(
   name: react,
-  platforms: [.iOS(.v15), .macCatalyst(SupportedPlatform.MacCatalystVersion.v13)],
+  platforms: [.iOS(.v15), .macOS(.v14), .macCatalyst(SupportedPlatform.MacCatalystVersion.v13)],
   products: [
     .library(
       name: react,
@@ -753,6 +769,7 @@ extension String {
   static let reactNativeModuleDom = "React-domnativemodule"
   static let reactAppDelegate = "React-RCTAppDelegate"
   static let reactSettings = "React-RCTSettings"
+  static let reactRCTUIKit = "React-RCTUIKit" // [macOS]
 }
 
 func relativeSearchPath(_ depth: Int, _ path: String) -> String {
@@ -792,6 +809,14 @@ extension Target {
         .define("USE_HERMES", to: "1"),
       ] + defines + cxxCommonHeaderPaths
 
+    // [macOS] Platform-specific framework linking for targets that need UIKit (iOS/visionOS) vs AppKit (macOS)
+    var conditionalLinkerSettings: [LinkerSetting] = linkerSettings
+    if name == "React-graphics-Apple" || name == "React-RCTUIKit" {
+      conditionalLinkerSettings.append(.linkedFramework("UIKit", .when(platforms: [.iOS, .visionOS])))
+      conditionalLinkerSettings.append(.linkedFramework("AppKit", .when(platforms: [.macOS])))
+    }
+    // macOS]
+
     return .target(
       name: name,
       dependencies: dependencies,
@@ -800,7 +825,7 @@ extension Target {
       sources: sources,
       publicHeadersPath: publicHeadersPath,
       cxxSettings: cxxSettings,
-      linkerSettings: linkerSettings
+      linkerSettings: conditionalLinkerSettings
     )
   }
 }

packages/react-native/scripts/ios-prebuild/cli.js

@@ -17,15 +17,21 @@ import type {BuildFlavor, Destination, Platform} from './types';
 const platforms /*: $ReadOnlyArray<Platform> */ = [
   'ios',
   'ios-simulator',
+  'macos', // [macOS]
   'mac-catalyst',
+  'visionos', // [macOS]
+  'visionos-simulator', // [macOS]
 ];
 
 // CI can't use commas in cache keys, so 'macOS,variant=Mac Catalyst' was creating troubles
 // This map that converts from platforms to valid Xcodebuild destinations.
 const platformToDestination /*: $ReadOnly<{|[Platform]: Destination|}> */ = {
   ios: 'iOS',
   'ios-simulator': 'iOS Simulator',
+  macos: 'macOS', // [macOS]
   'mac-catalyst': 'macOS,variant=Mac Catalyst',
+  visionos: 'xrOS', // [macOS]
+  'visionos-simulator': 'xrOS Simulator', // [macOS]
 };
 
 const cli = yargs