feat(appcheck): appcheck recaptcha enterprise support

packages/firebase_app_check/firebase_app_check/android/build.gradle

@@ -80,6 +80,7 @@ android {
     implementation platform("com.google.firebase:firebase-bom:${getRootProjectExtOrCoreProperty("FirebaseSDKVersion", firebaseCoreProject)}")
     implementation 'com.google.firebase:firebase-appcheck-debug'
     implementation 'com.google.firebase:firebase-appcheck-playintegrity'
+    implementation 'com.google.firebase:firebase-appcheck-recaptchaenterprise:16.0.0-beta01'
     implementation 'androidx.annotation:annotation:1.7.0'
   }
 }

packages/firebase_app_check/firebase_app_check/android/src/main/kotlin/io/flutter/plugins/firebase/appcheck/FirebaseAppCheckPlugin.kt

@@ -9,6 +9,7 @@ import com.google.firebase.FirebaseApp
 import com.google.firebase.appcheck.FirebaseAppCheck
 import com.google.firebase.appcheck.debug.DebugAppCheckProviderFactory
 import com.google.firebase.appcheck.playintegrity.PlayIntegrityAppCheckProviderFactory
+import com.google.firebase.appcheck.recaptchaenterprise.RecaptchaEnterpriseAppCheckProviderFactory
 import io.flutter.embedding.engine.plugins.FlutterPlugin
 import io.flutter.embedding.engine.plugins.FlutterPlugin.FlutterPluginBinding
 import io.flutter.plugin.common.BinaryMessenger
@@ -55,6 +56,7 @@ class FirebaseAppCheckPlugin :
     androidProvider: String?,
     appleProvider: String?,
     debugToken: String?,
+    recaptchaEnterpriseSiteKey: String?,
     callback: (Result<Unit>) -> Unit
   ) {
     try {
@@ -66,6 +68,16 @@ class FirebaseAppCheckPlugin :
             DebugAppCheckProviderFactory.getInstance()
           )
         }
+        "recaptchaEnterprise" -> {
+          if (recaptchaEnterpriseSiteKey != null) {
+            firebaseAppCheck.installAppCheckProviderFactory(
+              RecaptchaEnterpriseAppCheckProviderFactory.getInstance(recaptchaEnterpriseSiteKey)
+            )
+          } else {
+            callback(Result.failure(FlutterError("invalid-argument", "Site key is required for reCAPTCHA Enterprise", null)))
+            return
+          }
+        }
         else -> {
           firebaseAppCheck.installAppCheckProviderFactory(
             PlayIntegrityAppCheckProviderFactory.getInstance()

packages/firebase_app_check/firebase_app_check/android/src/main/kotlin/io/flutter/plugins/firebase/appcheck/GeneratedAndroidFirebaseAppCheck.g.kt

@@ -1,7 +1,7 @@
 // Copyright 2025, the Chromium project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-// Autogenerated from Pigeon (v25.3.2), do not edit directly.
+// Autogenerated from Pigeon (v26.3.4), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 @file:Suppress("UNCHECKED_CAST", "ArrayInDataClass")
 
@@ -49,7 +49,7 @@ class FlutterError (
   val code: String,
   override val message: String? = null,
   val details: Any? = null
-) : Throwable()
+) : RuntimeException()
 private open class GeneratedAndroidFirebaseAppCheckPigeonCodec : StandardMessageCodec() {
   override fun readValueOfType(type: Byte, buffer: ByteBuffer): Any? {
     return     super.readValueOfType(type, buffer)
@@ -62,7 +62,7 @@ private open class GeneratedAndroidFirebaseAppCheckPigeonCodec : StandardMessage
 
 /** Generated interface from Pigeon that represents a handler of messages from Flutter. */
 interface FirebaseAppCheckHostApi {
-  fun activate(appName: String, androidProvider: String?, appleProvider: String?, debugToken: String?, callback: (Result<Unit>) -> Unit)
+  fun activate(appName: String, androidProvider: String?, appleProvider: String?, debugToken: String?, recaptchaEnterpriseSiteKey: String?, callback: (Result<Unit>) -> Unit)
   fun getToken(appName: String, forceRefresh: Boolean, callback: (Result<String?>) -> Unit)
   fun setTokenAutoRefreshEnabled(appName: String, isTokenAutoRefreshEnabled: Boolean, callback: (Result<Unit>) -> Unit)
   fun registerTokenListener(appName: String, callback: (Result<String>) -> Unit)
@@ -86,7 +86,8 @@ interface FirebaseAppCheckHostApi {
             val androidProviderArg = args[1] as String?
             val appleProviderArg = args[2] as String?
             val debugTokenArg = args[3] as String?
-            api.activate(appNameArg, androidProviderArg, appleProviderArg, debugTokenArg) { result: Result<Unit> ->
+            val recaptchaEnterpriseSiteKeyArg = args[4] as String?
+            api.activate(appNameArg, androidProviderArg, appleProviderArg, debugTokenArg, recaptchaEnterpriseSiteKeyArg) { result: Result<Unit> ->
               val error = result.exceptionOrNull()
               if (error != null) {
                 reply.reply(GeneratedAndroidFirebaseAppCheckPigeonUtils.wrapError(error))

packages/firebase_app_check/firebase_app_check/example/android/build.gradle

@@ -1,5 +1,6 @@
 allprojects {
     repositories {
+        mavenLocal()
         google()
         mavenCentral()
     }

packages/firebase_app_check/firebase_app_check/example/android/settings.gradle

@@ -22,7 +22,7 @@ plugins {
     // START: FlutterFire Configuration
     id "com.google.gms.google-services" version "4.3.15" apply false
     // END: FlutterFire Configuration
-    id "org.jetbrains.kotlin.android" version "1.9.22" apply false
+    id "org.jetbrains.kotlin.android" version "2.1.0" apply false
 }
 
 include ":app"

packages/firebase_app_check/firebase_app_check/example/lib/main.dart

@@ -79,13 +79,21 @@ class _FirebaseAppCheck extends State<FirebaseAppCheckExample> {
   final appCheck = FirebaseAppCheck.instance;
   String _message = '';
   String _eventToken = 'not yet';
+  late final TextEditingController _siteKeyController;
 
   @override
   void initState() {
+    _siteKeyController = TextEditingController(text: kWebRecaptchaSiteKey);
     appCheck.onTokenChange.listen(setEventToken);
     super.initState();
   }
 
+  @override
+  void dispose() {
+    _siteKeyController.dispose();
+    super.dispose();
+  }
+
   void setMessage(String message) {
     setState(() {
       _message = message;
@@ -101,16 +109,25 @@ class _FirebaseAppCheck extends State<FirebaseAppCheckExample> {
   Future<void> _activate({
     AndroidAppCheckProvider? android,
     AppleAppCheckProvider? apple,
+    String? webProviderType,
     WindowsAppCheckProvider? windows,
   }) async {
     try {
+      dynamic providerWeb;
+      if (webProviderType == 'enterprise') {
+        providerWeb = ReCaptchaEnterpriseProvider(_siteKeyController.text);
+      } else if (webProviderType == 'v3') {
+        providerWeb = ReCaptchaV3Provider(_siteKeyController.text);
+      }
+
       await appCheck.activate(
         providerAndroid: android ?? const AndroidPlayIntegrityProvider(),
         providerApple: apple ?? const AppleDeviceCheckProvider(),
-        providerWeb: ReCaptchaV3Provider(kWebRecaptchaSiteKey),
+        providerWeb: providerWeb,
         providerWindows: windows ?? const WindowsDebugProvider(),
       );
       final providerName = windows?.runtimeType.toString() ??
+          webProviderType ??
           apple?.runtimeType.toString() ??
           android?.runtimeType.toString() ??
           'default';
@@ -170,6 +187,27 @@ class _FirebaseAppCheck extends State<FirebaseAppCheckExample> {
                   'activate(AppAttest + DeviceCheck fallback)',
                 ),
               ),
+            const SizedBox(height: 8),
+            TextField(
+              controller: _siteKeyController,
+              decoration: const InputDecoration(
+                labelText: 'reCAPTCHA Site Key',
+                border: OutlineInputBorder(),
+              ),
+            ),
+            const SizedBox(height: 8),
+            ElevatedButton(
+              onPressed: () => _activate(
+                android: AndroidReCaptchaEnterpriseProvider(siteKey: _siteKeyController.text),
+              ),
+              child: const Text('activate(Android reCAPTCHA Enterprise)'),
+            ),
+            ElevatedButton(
+              onPressed: () => _activate(
+                webProviderType: 'enterprise',
+              ),
+              child: const Text('activate(Web reCAPTCHA Enterprise)'),
+            ),
             const SizedBox(height: 16),
             const Text(
               'Actions',