[firebase_app_check]: 0.4.1 breaks token generation, and MacOS too, making it unusable

[jonmountjoy]

Is there an existing issue for this?

• I have searched the existing issues.

Which plugins are affected?

App Check

Which platforms are affected?

iOS

Description

My app has been using app check for the past year or two. Today, using firebase_app_check: 0.4.1, it no longer showed app check tokens when running on the simulator - they weren't in the Flutter logs, nor in Console attached to the device. Instead, it shows this error:

12.2.0 - [FirebaseAuth][I-AUT000018] Error getting App Check token; using placeholder token instead. 
Error: Error Domain=com.google.app_check_core Code=4 "The attestation provider DeviceCheckProvider
is not supported on current platform and OS version." 
UserInfo={NSLocalizedFailureReason=The attestation provider DeviceCheckProvider 
is not supported on current platform and OS version.}

As a result, I can no longer run my app, anywhere.

The simulator is an iPhone 17 running iOS 26.0.

If I revert that single dependency to firebase_app_check: 0.4.0+1, then it works as it used to, showing:

Firebase App Check Debug Token: D621364B-E786-4A22-AB22-1B7B06526A79

There is a second issue, which I'll open another issue for, which is that you can no longer see the token when the app runs on device, as the log system in MacOS 26 converts it to - which means I can no longer run my own builds on my own device :-(

Reproducing the issue

Run any app that uses firebase_app_check on MacOS attached to a Simulator.

Firebase Core version

4.1.1

Flutter Version

3.35.4

Relevant Log Output

Flutter dependencies

Expand Flutter dependencies snippet

Dart SDK 3.9.2
Flutter SDK 3.35.4
rules 2.1.1+169

dependencies:
- algolia 1.1.2 [meta http uuid universal_io]
- firebase_ai 3.2.0 [firebase_app_check firebase_auth firebase_core firebase_core_platform_interface flutter http meta web_socket_channel]
- firebase_app_check 0.4.0+1 [firebase_app_check_platform_interface firebase_app_check_web firebase_core firebase_core_platform_interface flutter]
- firebase_auth 6.1.0 [firebase_auth_platform_interface firebase_auth_web firebase_core firebase_core_platform_interface flutter meta]
- firebase_core 4.1.1 [firebase_core_platform_interface firebase_core_web flutter meta]
- firebase_crashlytics 5.0.2 [firebase_core firebase_core_platform_interface firebase_crashlytics_platform_interface flutter stack_trace]
- firebase_messaging 16.0.2 [firebase_core firebase_core_platform_interface firebase_messaging_platform_interface firebase_messaging_web flutter meta]
- firebase_storage 13.0.2 [firebase_core firebase_core_platform_interface firebase_storage_platform_interface firebase_storage_web flutter]
- flex_color_picker 3.7.1 [flex_seed_scheme flutter]
- flex_seed_scheme 3.5.1 [collection flutter meta]
- flutter 0.0.0 [characters collection material_color_utilities meta vector_math sky_engine]
- uuid 4.5.1 [crypto sprintf meta fixnum]
- device_info_plus 12.1.0 [device_info_plus_platform_interface ffi file flutter flutter_web_plugins meta web win32 win32_registry]
- ....

transitive dependencies:
- _flutterfire_internals 1.3.62 [collection firebase_core firebase_core_platform_interface flutter meta]
- connectivity_plus_platform_interface 2.0.1 [flutter meta plugin_platform_interface]
- file 7.0.1 [meta path]
- file_selector_linux 0.9.3+2 [cross_file file_selector_platform_interface flutter]
- file_selector_macos 0.9.4+4 [cross_file file_selector_platform_interface flutter]
- file_selector_platform_interface 2.6.2 [cross_file flutter http plugin_platform_interface]
- file_selector_windows 0.9.3+4 [cross_file file_selector_platform_interface flutter]
- firebase_app_check_platform_interface 0.2.1 [_flutterfire_internals firebase_core flutter meta plugin_platform_interface]
- firebase_app_check_web 0.2.1 [_flutterfire_internals firebase_app_check_platform_interface firebase_core firebase_core_web flutter flutter_web_plugins web]
- firebase_auth_platform_interface 8.1.2 [_flutterfire_internals collection firebase_core flutter http meta plugin_platform_interface]
- firebase_auth_web 6.0.3 [firebase_auth_platform_interface firebase_core firebase_core_web flutter flutter_web_plugins http_parser meta web]
- firebase_core_platform_interface 6.0.1 [collection flutter flutter_test meta plugin_platform_interface]
- firebase_core_web 3.1.1 [firebase_core_platform_interface flutter flutter_web_plugins meta web]
- firebase_crashlytics_platform_interface 3.8.13 [_flutterfire_internals collection firebase_core flutter meta plugin_platform_interface]
- firebase_messaging_platform_interface 4.7.2 [_flutterfire_internals firebase_core flutter meta plugin_platform_interface]
- firebase_messaging_web 4.0.2 [_flutterfire_internals firebase_core firebase_core_web firebase_messaging_platform_interface flutter flutter_web_plugins meta web]
- firebase_storage_platform_interface 5.2.13 [_flutterfire_internals collection firebase_core flutter meta plugin_platform_interface]
- firebase_storage_web 3.10.20 [_flutterfire_internals async firebase_core firebase_core_web firebase_storage_platform_interface flutter flutter_web_plugins http meta web]
- fixnum 1.1.1
- flutter_cache_manager 3.4.1 [clock collection file flutter http path path_provider rxdart sqflite uuid]

...

Additional context and comments

No response

[SelaseKay]

Hi @jonmountjoy, kindly provide a minimal reproducible example for this issue.

[jamieownsu]

i am experiencing the exact same issue

[FXschwartz]

Running into the same issue, upgrading to 0.4.1 no longer shows debug app check token when running on debug mode on simulator or physical device. Downgrading to 0.4.0 shows the debug token again.

[SelaseKay]

Hi @FXschwartz, could you share a reproducible sample?

[FXschwartz]

Hi @FXschwartz, could you share a reproducible sample?

I create a public repo here - https://github.com/FXschwartz/appcheck-debug

You will need to add firebase account values to the firebase_options.dart file otherwise you will get exceptions when running the app. The app check version is currently set to the latest 0.4.1 and when running you will see no debug token generated and logged. But downgrading down to 0.4.0 will correctly generate and log the debug token with instructions to add it to the firebase console.

I created this app via

1. flutter create appcheck_debug
2. Navigated to the root of the new directory and ran flutter pub add firebase_core
3. Added firebase_app_check: 0.4.1 to pubspec.yaml
4. Added the following code to main.dart

  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
  await FirebaseAppCheck.instance.activate(
    webProvider: ReCaptchaV3Provider('recaptcha-v3-site-key'),
    // Default provider for Android is the Play Integrity provider. You can use the "AndroidProvider" enum to choose
    // your preferred provider. Choose from:
    // 1. Debug provider
    // 2. Safety Net provider
    // 3. Play Integrity provider
    androidProvider: AndroidProvider.debug,
    // androidProvider: AndroidProvider.debug,
    // Default provider for iOS/macOS is the Device Check provider. You can use the "AppleProvider" enum to choose
    // your preferred provider. Choose from:
    // 1. Debug provider
    // 2. Device Check provider
    // 3. App Attest provider
    // 4. App Attest provider with fallback to Device Check provider (App Attest provider is only available on iOS 14.0+, macOS 14.0+)
    appleProvider: AppleProvider.debug,
  );

5. Created firebase_options.dart file with these contents

// File generated by FlutterFire CLI.
// ignore_for_file: lines_longer_than_80_chars, avoid_classes_with_only_static_members
import 'package:firebase_core/firebase_core.dart' show FirebaseOptions;
import 'package:flutter/foundation.dart'
    show defaultTargetPlatform, kIsWeb, TargetPlatform;

/// Default [FirebaseOptions] for use with your Firebase apps.
///
/// Example:
/// ```dart
/// import 'firebase_options.dart';
/// // ...
/// await Firebase.initializeApp(
///   options: DefaultFirebaseOptions.currentPlatform,
/// );
/// ```
class DefaultFirebaseOptions {
  static FirebaseOptions get currentPlatform {
    if (kIsWeb) {
      throw UnsupportedError(
        'DefaultFirebaseOptions have not been configured for web - '
        'you can reconfigure this by running the FlutterFire CLI again.',
      );
    }
    switch (defaultTargetPlatform) {
      case TargetPlatform.android:
        return android;
      case TargetPlatform.iOS:
        return ios;
      case TargetPlatform.macOS:
        throw UnsupportedError(
          'DefaultFirebaseOptions have not been configured for macos - '
          'you can reconfigure this by running the FlutterFire CLI again.',
        );
      case TargetPlatform.windows:
        throw UnsupportedError(
          'DefaultFirebaseOptions have not been configured for windows - '
          'you can reconfigure this by running the FlutterFire CLI again.',
        );
      case TargetPlatform.linux:
        throw UnsupportedError(
          'DefaultFirebaseOptions have not been configured for linux - '
          'you can reconfigure this by running the FlutterFire CLI again.',
        );
      default:
        throw UnsupportedError(
          'DefaultFirebaseOptions are not supported for this platform.',
        );
    }
  }

  static const FirebaseOptions android = FirebaseOptions(
    apiKey: '',
    appId: '',
    messagingSenderId: '',
    projectId: '',
    storageBucket: '',
  );

  static const FirebaseOptions ios = FirebaseOptions(
    apiKey: '',
    appId: '',
    messagingSenderId: '',
    projectId: '',
    storageBucket: '',
    iosClientId: '',
    iosBundleId: '',
  );
}

[jonmountjoy]

I have found out how to fix this. I suspect a bug was introduced in this commit which somehow makes the appleProvider argument not work. Note that particular argument is deprecated here (but nobody will see that as it's not user-facing).

The workaround is to use the new argument, which goes like this:
providerApple: const AppleDebugProvider(debugToken: 'appleDebug')

You'll see this in the updated example app, but the Flutter documentation is wrong - it doesn't show that this is even possible, and instead provides the deprecated (and not functioning) way of doing things.

So ideally two things should change:

• the "old" appleProvider should not stop working - it should be deprecated, not bug out.
• the documentation should be fixed

[SelaseKay]

Exactly. We missed deprecating the appleProvider and androidProvider fields in the user-facing API (activate) in our latest release. I’ll create a PR to address that.

In the meantime, please use: providerApple: const AppleDebugProvider(debugToken: 'your-pregenerated-token') Only include a debugToken if you’re working with a pregenerated token. Otherwise, you can simply do: providerApple: const AppleDebugProvider() . A debug token will then be printed in your console. Apologies for any inconvenience caused.