feat: add support for bridgeless mode (#1793)

Starting with 0.73, bridgeless mode can now be enabled:

- **Android:** In `gradle.properties`:
  ```gradle
  newArchEnabled=true
  bridgelessEnabled=true
  ```

- **iOS:** In `Podfile`:
  ```ruby
  options = {
    :bridgeless_enabled => true,
    :fabric_enabled => true,
    :hermes_enabled => false,
  }

  use_test_app! options
  ```

See the full announcement here:
https://reactnative.dev/blog/2023/12/06/0.73-debugging-improvements-stable-symlinks#new-architecture-updates

Gemfile.lock

@@ -55,4 +55,4 @@ DEPENDENCIES
   xcodeproj
 
 BUNDLED WITH
-   2.4.10
+   2.5.4

android/app/build.gradle

@@ -118,6 +118,7 @@ android {
         buildConfigField "String", "ReactTestApp_singleApp", singleApp ? "\"${singleApp}\"" : "null"
 
         buildConfigField "boolean", "ReactTestApp_useFabric", enableNewArchitecture.toString()
+        buildConfigField "boolean", "ReactTestApp_useBridgeless", enableBridgeless.toString()
 
         resValue "string", "app_name", project.ext.react.appName
 
@@ -206,7 +207,11 @@ android {
         main.java.srcDirs += [
             project.ext.react.enableCamera ? "src/camera/java" : "src/no-camera/java",
 
-            enableNewArchitecture ? "src/new-arch/java" : "src/old-arch/java",
+            !enableNewArchitecture
+                ? "src/old-arch/java"
+                : enableBridgeless
+                    ? "src/new-arch-0.73/java"
+                    : "src/new-arch/java",
 
             // TODO: Remove this block when we drop support for 0.67
             // https://github.com/facebook/react-native/commit/ce74aa4ed335d4c36ce722d47937b582045e05c4

android/app/src/new-arch-0.73/java/com/microsoft/reacttestapp/compat/ReactNativeHostCompat.kt

@@ -0,0 +1,30 @@
+package com.microsoft.reacttestapp.compat
+
+import android.app.Application
+import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint
+import com.facebook.react.defaults.DefaultReactNativeHost
+import com.facebook.soloader.SoLoader
+import com.microsoft.reacttestapp.BuildConfig
+
+abstract class ReactNativeHostCompat(application: Application) : DefaultReactNativeHost(
+    application
+) {
+    companion object {
+        init {
+            try {
+                DefaultNewArchitectureEntryPoint.load(
+                    turboModulesEnabled = BuildConfig.ReactTestApp_useFabric,
+                    fabricEnabled = BuildConfig.ReactTestApp_useFabric,
+                    bridgelessEnabled = BuildConfig.ReactTestApp_useBridgeless
+                )
+            } catch (e: UnsatisfiedLinkError) {
+                // Older versions of `DefaultNewArchitectureEntryPoint` is
+                // hard coded to load `libappmodules.so`
+            }
+            SoLoader.loadLibrary("reacttestapp_appmodules")
+        }
+    }
+
+    override val isNewArchEnabled: Boolean = BuildConfig.ReactTestApp_useFabric
+    override val isHermesEnabled: Boolean? = true
+}

android/app/src/new-arch-0.73/java/com/microsoft/reacttestapp/fabric/ComponentsRegistry.kt

@@ -0,0 +1,36 @@
+package com.microsoft.reacttestapp.fabric
+
+import com.facebook.jni.HybridData
+import com.facebook.proguard.annotations.DoNotStrip
+import com.facebook.react.fabric.ComponentFactory
+import com.facebook.soloader.SoLoader
+
+/**
+ * The corresponding C++ implementation is in `android/app/src/main/jni/ComponentsRegistry.cpp`
+ */
+@DoNotStrip
+class ComponentsRegistry @DoNotStrip private constructor(
+    componentFactory: ComponentFactory
+) {
+    companion object {
+        @DoNotStrip
+        fun register(componentFactory: ComponentFactory): ComponentsRegistry {
+            return ComponentsRegistry(componentFactory)
+        }
+
+        init {
+            SoLoader.loadLibrary("fabricjni")
+            SoLoader.loadLibrary("reacttestapp_appmodules")
+        }
+    }
+
+    @DoNotStrip
+    private val mHybridData: HybridData
+
+    @DoNotStrip
+    private external fun initHybrid(componentFactory: ComponentFactory): HybridData
+
+    init {
+        mHybridData = initHybrid(componentFactory)
+    }
+}

android/app/src/new-arch-0.73/java/com/microsoft/reacttestapp/turbomodule/TurboModuleManagerDelegate.kt

@@ -0,0 +1,39 @@
+package com.microsoft.reacttestapp.turbomodule
+
+import com.facebook.jni.HybridData
+import com.facebook.react.ReactPackage
+import com.facebook.react.ReactPackageTurboModuleManagerDelegate
+import com.facebook.react.bridge.ReactApplicationContext
+
+/**
+ * These type aliases are here to prevent `@react-native-community/cli` from
+ * marking them as native modules to autolink.
+ *
+ * See also `matchClassName` in
+ * https://github.com/react-native-community/cli/blob/8.x/packages/platform-android/src/config/findPackageClassName.ts#L25
+ */
+typealias PackagesList = List<ReactPackage?>
+typealias ReactTurboModuleManagerDelegate = ReactPackageTurboModuleManagerDelegate
+typealias ReactTurboModuleManagerDelegateBuilder = ReactPackageTurboModuleManagerDelegate.Builder
+
+/**
+ * The corresponding C++ implementation is in `android/app/src/main/jni/TurboModuleManagerDelegate.cpp`
+ */
+class TurboModuleManagerDelegate protected constructor(
+    reactApplicationContext: ReactApplicationContext?,
+    packages: PackagesList?
+) : ReactTurboModuleManagerDelegate(reactApplicationContext, packages) {
+
+    external override fun initHybrid(): HybridData?
+
+    external fun canCreateTurboModule(moduleName: String?): Boolean
+
+    class Builder : ReactTurboModuleManagerDelegateBuilder() {
+        override fun build(
+            context: ReactApplicationContext?,
+            packages: PackagesList?
+        ): TurboModuleManagerDelegate {
+            return TurboModuleManagerDelegate(context, packages)
+        }
+    }
+}

android/dependencies.gradle

@@ -72,6 +72,7 @@ ext {
     reactNativeVersion = getPackageVersionNumber("react-native", rootDir)
     autodetectReactNativeVersion = reactNativeVersion == 0 || reactNativeVersion >= v(0, 71, 0)
     enableNewArchitecture = isNewArchitectureEnabled(project)
+    enableBridgeless = isBridgelessEnabled(project, enableNewArchitecture)
     usePrefabs = reactNativeVersion == 0 || reactNativeVersion >= v(0, 71, 0)
 
     androidPluginVersion = getDefaultGradlePluginVersion(reactNativeVersion)

android/test-app-util.gradle

@@ -243,6 +243,26 @@ ext.getVersionName = {
     return "1.0"
 }
 
+ext.isBridgelessEnabled = { project, isNewArchEnabled ->
+    if (isNewArchEnabled) {
+        def reactBridgelessEnabled = tryGetProperty(project, "react.bridgelessEnabled")
+        def bridgelessEnabled = tryGetProperty(project, "bridgelessEnabled")
+        if (reactBridgelessEnabled == "true" || bridgelessEnabled == "true") {
+            def version = getPackageVersionNumber("react-native", project.rootDir)
+            def isSupported = version == 0 || version >= v(0, 73, 0)
+            if (!isSupported) {
+                logger.warn([
+                    "react-native 0.73 or greater is required for Bridgeless",
+                    "Mode — disable `bridgelessEnabled` in your",
+                    "`gradle.properties` or upgrade `react-native`"
+                ].join(" "))
+            }
+            return isSupported
+        }
+    }
+    return false
+}
+
 ext.isFabricEnabled = { project ->
     return isNewArchitectureEnabled(project)
 }

example/App.tsx

@@ -88,7 +88,7 @@ function testID(label: string): string {
 }
 
 function useIsFabricComponent() {
-  const [isFabric, setIsFabric] = useState(false);
+  const [isFabric, setIsFabric] = useState(isBridgeless());
   const setter = useCallback(
     ({ currentTarget }: NativeSyntheticEvent<unknown>) => {
       setIsFabric(isFabricInstance(currentTarget));
@@ -210,6 +210,8 @@ export function App({
             <Feature value={isOnOrOff(isFabric && concurrentRoot)}>
               Concurrent React
             </Feature>
+            <Separator />
+            <Feature value={isOnOrOff(isBridgeless())}>Bridgeless</Feature>
           </View>
         </ScrollView>
       </SafeAreaView>

example/android/gradle.properties

@@ -41,6 +41,7 @@ reactNativeArchitectures=armeabi-v7a,arm64-v8a,x86,x86_64
 # are providing them.
 # Note that this is incompatible with web debugging.
 #newArchEnabled=true
+#bridgelessEnabled=true
 
 # Uncomment the line below if building react-native from source
 #ANDROID_NDK_VERSION=26.1.10909125

example/ios/Podfile

@@ -3,6 +3,7 @@ require_relative '../node_modules/react-native-test-app/test_app'
 workspace 'Example.xcworkspace'
 
 options = {
+  :bridgeless_enabled => false,
   :fabric_enabled => false,
   :hermes_enabled => false,
 }

example/ios/Podfile.lock

@@ -1020,7 +1020,7 @@ PODS:
     - React-jsi (= 0.73.2)
     - React-logger (= 0.73.2)
     - React-perflogger (= 0.73.2)
-  - ReactNativeHost (0.4.0):
+  - ReactNativeHost (0.4.2):
     - React-Core
     - React-cxxreact
     - ReactCommon/turbomodule/core
@@ -1248,12 +1248,12 @@ SPEC CHECKSUMS:
   React-runtimescheduler: 6517c0cdfae3ea29b599759e069ae97746163248
   React-utils: f5bc61e7ea3325c0732ae2d755f4441940163b85
   ReactCommon: a42e89b49d88c3890dfb6fd98a33ac80d555be19
-  ReactNativeHost: e17481b59ed2f3a1c65db1e83f03c1abf9afcd14
+  ReactNativeHost: 87c7181cb3b0ce016e094ede3cc03b4f61c97dd5
   ReactTestApp-DevSupport: 684f374b53c868cd08a0337839a7fcc5ce1e25aa
   ReactTestApp-Resources: da77347b3f02b5d79ba3fecb3ad328b2f6a7ef4d
   SocketRocket: f32cd54efbe0f095c4d7594881e52619cfe80b17
   Yoga: 13c8ef87792450193e117976337b8527b49e8c03
 
-PODFILE CHECKSUM: 66243ee27b434ad0f296253272b27b383190853c
+PODFILE CHECKSUM: 0f9a8fd4217f943391e46a62ec8cad034e331d4f
 
 COCOAPODS: 1.14.2

example/macos/Podfile.lock

@@ -1018,7 +1018,7 @@ PODS:
     - React-jsi (= 0.73.6)
     - React-logger (= 0.73.6)
     - React-perflogger (= 0.73.6)
-  - ReactNativeHost (0.4.0):
+  - ReactNativeHost (0.4.2):
     - React-Core
     - React-cxxreact
     - ReactCommon/turbomodule/core
@@ -1242,7 +1242,7 @@ SPEC CHECKSUMS:
   React-runtimescheduler: 06ca3657c857fb14d00ec548c489f3b8c552601e
   React-utils: 68f5b33b6957324718290e3c7eda822db1da9b56
   ReactCommon: e80b030b22caf9def0e375bb5a46c02305b95e10
-  ReactNativeHost: e17481b59ed2f3a1c65db1e83f03c1abf9afcd14
+  ReactNativeHost: 87c7181cb3b0ce016e094ede3cc03b4f61c97dd5
   ReactTestApp-DevSupport: 684f374b53c868cd08a0337839a7fcc5ce1e25aa
   ReactTestApp-Resources: 8539dac0f8d2ef3821827a537e37812104c6ff78
   SocketRocket: abac6f5de4d4d62d24e11868d7a2f427e0ef940d

example/package.json

@@ -45,7 +45,7 @@
     "kitType": "app",
     "alignDeps": {
       "requirements": [
-        "react-native@0.72"
+        "react-native@0.73"
       ],
       "capabilities": [
         "core-android",

ios/ReactTestApp/ReactInstance.swift

@@ -27,10 +27,6 @@ final class ReactInstance: NSObject, RNXHostConfig {
 
         super.init()
 
-        #if USE_FABRIC
-        RCTEnableTurboModule(true)
-        #endif
-
         NotificationCenter.default.addObserver(
             self,
             selector: #selector(onJavaScriptLoaded(_:)),

ios/pod_helpers.rb

@@ -1,3 +1,10 @@
+def bridgeless_enabled?(options, react_native_version)
+  return false unless new_architecture_enabled?(options, react_native_version)
+
+  supports_bridgeless = react_native_version.zero? || react_native_version >= v(0, 73, 0)
+  supports_bridgeless && options[:bridgeless_enabled]
+end
+
 def find_file(file_name, current_dir)
   return if current_dir.expand_path.to_s == '/'
 
@@ -40,9 +47,8 @@ def try_pod(name, podspec, project_root)
   pod name, :podspec => podspec if File.exist?(File.join(project_root, podspec))
 end
 
-def use_new_architecture!(options)
-  new_arch_enabled = new_architecture_enabled?(options, v(1_000, 0, 0))
-  return unless new_arch_enabled
+def use_new_architecture!(options, react_native_version)
+  return unless new_architecture_enabled?(options, react_native_version)
 
   Pod::UI.warn(
     'As of writing, New Architecture (Fabric) is still experimental and ' \
@@ -53,6 +59,7 @@ def use_new_architecture!(options)
   options[:fabric_enabled] = true
   options[:new_arch_enabled] = true
   ENV['RCT_NEW_ARCH_ENABLED'] = '1'
+  ENV['USE_BRIDGELESS'] = '1' if bridgeless_enabled?(options, react_native_version)
 end
 
 def v(major, minor, patch)

ios/test_app.rb

@@ -198,7 +198,8 @@ def use_react_native!(project_root, target_platform, options)
   include_react_native!(**options,
                         app_path: find_file('package.json', project_root).parent.to_s,
                         path: react_native.relative_path_from(project_root).to_s,
-                        rta_project_root: project_root)
+                        rta_project_root: project_root,
+                        version: version)
 end
 
 def make_project!(xcodeproj, project_root, target_platform, options)
@@ -304,6 +305,7 @@ def make_project!(xcodeproj, project_root, target_platform, options)
   build_settings['PRODUCT_BUILD_NUMBER'] = build_number || '1'
 
   use_new_arch = new_architecture_enabled?(options, rn_version)
+  use_bridgeless = bridgeless_enabled?(options, rn_version)
   app_project = Xcodeproj::Project.open(xcodeproj_dst)
   app_project.native_targets.each do |target|
     case target.name
@@ -327,6 +329,9 @@ def make_project!(xcodeproj, project_root, target_platform, options)
           config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] << 'FOLLY_NO_CONFIG=1'
           config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] << 'RCT_NEW_ARCH_ENABLED=1'
           config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] << 'USE_FABRIC=1'
+          if use_bridgeless
+            config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] << 'USE_BRIDGELESS=1'
+          end
         end
 
         build_settings.each do |setting, value|
@@ -335,6 +340,7 @@ def make_project!(xcodeproj, project_root, target_platform, options)
 
         config.build_settings['OTHER_SWIFT_FLAGS'] ||= ['$(inherited)']
         config.build_settings['OTHER_SWIFT_FLAGS'] << '-DUSE_FABRIC' if use_new_arch
+        config.build_settings['OTHER_SWIFT_FLAGS'] << '-DUSE_BRIDGELESS' if use_bridgeless
         if single_app.is_a? String
           config.build_settings['OTHER_SWIFT_FLAGS'] << '-DENABLE_SINGLE_APP_MODE'
         end

ios/use_react_native-0.71.rb

@@ -3,11 +3,11 @@ require 'open3'
 require_relative('pod_helpers')
 
 def include_react_native!(options)
-  react_native, project_root = options.values_at(:path, :rta_project_root)
+  react_native, project_root, version = options.values_at(:path, :rta_project_root, :version)
 
   require_relative(File.join(project_root, react_native, 'scripts', 'react_native_pods'))
 
-  use_new_architecture!(options)
+  use_new_architecture!(options, version)
   use_react_native!(
     path: react_native,
     fabric_enabled: options[:fabric_enabled] == true,

package.json

@@ -80,7 +80,7 @@
     "test:rb": "bundle exec ruby -Ilib:test -e \"Dir.glob('./test/test_*.rb').each { |file| require(file) }\""
   },
   "dependencies": {
-    "@rnx-kit/react-native-host": "^0.4.0",
+    "@rnx-kit/react-native-host": "^0.4.2",
     "ajv": "^8.0.0",
     "chalk": "^4.1.0",
     "cliui": "^8.0.0",

test/pack.test.mjs

@@ -77,6 +77,9 @@ describe("npm pack", () => {
       "android/app/src/main/res/values/colors.xml",
       "android/app/src/main/res/values/strings.xml",
       "android/app/src/main/res/values/styles.xml",
+      "android/app/src/new-arch-0.73/java/com/microsoft/reacttestapp/compat/ReactNativeHostCompat.kt",
+      "android/app/src/new-arch-0.73/java/com/microsoft/reacttestapp/fabric/ComponentsRegistry.kt",
+      "android/app/src/new-arch-0.73/java/com/microsoft/reacttestapp/turbomodule/TurboModuleManagerDelegate.kt",
       "android/app/src/new-arch/java/com/microsoft/reacttestapp/compat/ReactNativeHostCompat.kt",
       "android/app/src/new-arch/java/com/microsoft/reacttestapp/fabric/ComponentsRegistry.kt",
       "android/app/src/new-arch/java/com/microsoft/reacttestapp/turbomodule/TurboModuleManagerDelegate.kt",

test/test_pod_helpers.rb

@@ -3,25 +3,49 @@ require('minitest/autorun')
 require_relative('../ios/pod_helpers')
 
 class TestPodHelpers < Minitest::Test
+  def test_bridgeless_enabled?
+    ENV.delete('RCT_NEW_ARCH_ENABLED')
+
+    # Bridgeless mode is first publicly available in 0.73
+    available_version = v(0, 73, 0)
+
+    refute(bridgeless_enabled?({}, 0))
+    refute(bridgeless_enabled?({}, available_version))
+
+    options = { :bridgeless_enabled => true, :fabric_enabled => true }
+
+    refute(bridgeless_enabled?(options, v(0, 72, 999)))
+    assert(bridgeless_enabled?(options, available_version))
+
+    # `RCT_NEW_ARCH_ENABLED` does not enable bridgeless
+    ENV['RCT_NEW_ARCH_ENABLED'] = '1'
+
+    refute(bridgeless_enabled?({}, v(0, 72, 999)))
+    refute(bridgeless_enabled?({}, available_version))
+  end
+
   def test_new_architecture_enabled?
     ENV.delete('RCT_NEW_ARCH_ENABLED')
 
+    # New architecture is first publicly available in 0.68, but we'll require 0.71
+    available_version = v(0, 71, 0)
+
     refute(new_architecture_enabled?({}, 0))
-    refute(new_architecture_enabled?({}, v(0, 71, 0)))
+    refute(new_architecture_enabled?({}, available_version))
 
     # New architecture is first publicly available in 0.68, but we'll require 0.71
     refute(new_architecture_enabled?({ :fabric_enabled => true }, v(0, 70, 999)))
-    assert(new_architecture_enabled?({ :fabric_enabled => true }, v(0, 71, 0)))
+    assert(new_architecture_enabled?({ :fabric_enabled => true }, available_version))
 
     # TODO: `:turbomodule_enabled` is scheduled for removal in 4.0
     refute(new_architecture_enabled?({ :turbomodule_enabled => true }, v(0, 70, 999)))
-    assert(new_architecture_enabled?({ :turbomodule_enabled => true }, v(0, 71, 0)))
+    assert(new_architecture_enabled?({ :turbomodule_enabled => true }, available_version))
 
     # `RCT_NEW_ARCH_ENABLED` enables everything
     ENV['RCT_NEW_ARCH_ENABLED'] = '1'
 
     refute(new_architecture_enabled?({}, v(0, 70, 999)))
-    assert(new_architecture_enabled?({}, v(0, 71, 0)))
+    assert(new_architecture_enabled?({}, available_version))
   end
 
   def test_v

yarn.lock

@@ -3292,12 +3292,12 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@rnx-kit/react-native-host@npm:^0.4.0":
-  version: 0.4.0
-  resolution: "@rnx-kit/react-native-host@npm:0.4.0"
+"@rnx-kit/react-native-host@npm:^0.4.2":
+  version: 0.4.2
+  resolution: "@rnx-kit/react-native-host@npm:0.4.2"
   peerDependencies:
     react-native: ">=0.66"
-  checksum: 7a03ee90caacf6f015e1c720ca8e1b50ff7af866265d01079ee4ef0f9689884e7839dd83940ffa97462232e5913f152a3a17b3975dd7b1aebb83f7a3ac88dae4
+  checksum: 691a7b66791d976c07036f67c95947ee7828dfe63c6d8a94edfda8dfb08b87795dd0762df4f96032e668c71114eb4608090bb445f0d53f0744667b31604d2432
   languageName: node
   linkType: hard
 
@@ -12087,7 +12087,7 @@ __metadata:
     "@microsoft/eslint-plugin-sdl": "npm:^0.2.0"
     "@react-native-community/cli": "npm:^12.3.0"
     "@rnx-kit/eslint-plugin": "npm:^0.6.0"
-    "@rnx-kit/react-native-host": "npm:^0.4.0"
+    "@rnx-kit/react-native-host": "npm:^0.4.2"
     "@rnx-kit/tsconfig": "npm:^1.0.0"
     "@types/js-yaml": "npm:^4.0.5"
     "@types/mustache": "npm:^4.0.0"