[BUG ❌ /With a possible fix ✔️ with a PR]: appFlavor null 🤔

[henriquetroiano]

Below is my full report.

This issue also happened with my Flutter app, so I created another project to double-check. 👍

👀 The possible solution is at the end of this report.

Flutter: 3.29.3 ✔️

A few dependencies for testing (all latest versions):

firebase_core: ^4.2.1
firebase_messaging: ^16.0.4
flutter_flavorizr: ^2.4.1

Flavorizr config in pubspec.yaml:

flavorizr:
  ide: "vscode"
  flavors:
    first:
      app:
        name: "MyFirstWhiteLabel"
      android:
        applicationId: "whitelabel.first"
        icon: "assets/white_labels/first/1024.jpg"
        firebase:
          config: "assets/white_labels/first/google-services.json"

      ios:
        bundleId: "whitelabel.first"
        icon: "assets/white_labels/first/1024.jpg"
        firebase:
          config: "assets/white_labels/first/GoogleService-Info.plist"

    second:
      app:
        name: "MySecondWhiteLabel"
      android:
        applicationId: "whitelabel.second"
        icon: "assets/white_labels/second/1024.png"
        firebase:
          config: "assets/white_labels/second/google-services.json"

      ios:
        bundleId: "whitelabel.second"
        icon: "assets/white_labels/second/1024.png"
        firebase:
          config: "assets/white_labels/second/GoogleService-Info.plist"

Commands I ran (the full default sequence):

flutter pub run flutter_flavorizr -p assets:download,assets:extract,android:androidManifest,android:flavorizrGradle,android:buildGradle,android:dummyAssets,android:icons,flutter:flavors,flutter:app,flutter:pages,flutter:main,ios:podfile,ios:xcconfig,ios:buildTargets,ios:schema,ios:dummyAssets,ios:icons,ios:plist,ios:launchScreen,macos:podfile,macos:xcconfig,macos:configs,macos:buildTargets,macos:schema,macos:dummyAssets,macos:icons,macos:plist,google:firebase,huawei:agconnect,assets:clean,ide:config

Here is my simple main.dart:

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import 'app.dart';
import 'flavors.dart';
import 'package:firebase_core/firebase_core.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  print("Firebase Apps length: ${Firebase.apps.length}");
  await Firebase.initializeApp();
  print("Firebase initialized: Apps length: ${Firebase.apps.length}");

  print("App flavor: $appFlavor");
  F.appFlavor = Flavor.values.firstWhere(
    (element) => element.name == appFlavor,
  );
  print("F app flavor: ${F.appFlavor}");

  runApp(const App());
}

Xcode output and error:

flutter: The Dart VM service is listening on http://127.0.0.1:53666/xAp5ztKlMyM=/
flutter: Firebase Apps length: 0
flutter: Firebase initialized: Apps length: 1
flutter: App flavor: null
[ERROR:flutter/runtime/dart_vm_initializer.cc(40)] Unhandled Exception: Bad state: No element
#0      ListBase.firstWhere (dart:collection/list.dart:132:5)
#1      main (package:testing_flavorizr/main.dart:17:31)
<asynchronous suspension>

This error is expected ❌ because appFlavor is null.

I was able to fix the issue ✔️ by modifying the flavor/Mode xcconfig file
(example: ios/Flutter/secondDebug.xcconfig):

#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
#include "Generated.xcconfig"

ASSET_PREFIX=second
BUNDLE_NAME=MySecondWhiteLabel
BUNDLE_DISPLAY_NAME=MySecondWhiteLabel
DART_DEFINES=$(inherited),RkxVVFRFUl9BUFBfRkxBVk9SPXNlY29uZA==

The Base64 string above is the encoded key-value pair:

FLUTTER_APP_FLAVOR=second

I’m not sure whether this is the correct fix, but after adding it I was able to build successfully. 🤔

If this is indeed the right approach, I’d be happy to submit a PR. 👍

[AngeloAvv]

Hey @henriquetroiano , can you tell me how you're launching your flavoured apps, please?

Also, can you create a sample repository I can check to try to reproduce the error? Since you're using Firebase secrets, you can anonymize your data as well

[henriquetroiano]

Hey @AngeloAvv , I'm launching through XCode as we used to. We just select the target Runner and then select the scheme X (where X is the flavor).

• And yes, of course! I've provided the project I've created for test in this repo: https://github.com/henriquetroiano/testing_flavorizr_ios_xcode

⚠️ Replace google-services.json and GoogleService-Info.plist files with content /// FILL HERE to your own content.
⚠️ This code will likely run, but if you regenerate the flavors, it will not detect the appFlavor on the flutter's main.dart unless you make the changes on .xcconfig files.

ℹ️ XCode Version: 26.0
ℹ️ Cocapods version: 1.16.2

[henriquetroiano]

I'm bypassing this problem by adding this to my Info.plist:

<key>FLUTTER_APP_FLAVOR</key>
<string>$(FLUTTER_APP_FLAVOR)</string>

and adding FLUTTER_APP_FLAVOR + DART_DEFINES (with fake value) to the variables section of my pubspec.yaml:

mynewapp:
      app:
        name: "My New APP"
      android:
        applicationId: "com.mynewapp"
        icon: "assets/white_labels/mynewapp/1024.png"
        firebase:
          config: "assets/white_labels/mynewapp/google-services.json"

      ios:
        bundleId: "com.mynewapp"
        variables:
          FLUTTER_APP_FLAVOR:
            value: "mynewapp"
          DART_DEFINES:
            value: "Tk9UX0VNUFRZX0RBUlRfREVGSU5FUz15ZXM="
        icon: "assets/white_labels/mynewapp/1024.png"
        firebase:
          config: "assets/white_labels/mynewapp/GoogleService-Info.plist"

You need to provide a DART_DEFINES in addition to FLUTTER_APP_FLAVOR, because without DART_DEFINES you got an error like: "Improperly formatted define flag"

The value provided to DART_DEFINES (Tk9UX0VNUFRZX0RBUlRfREVGSU5FUz15ZXM=) is just a base64 representation of "NOT_EMPTY_DART_DEFINES=yes", just to dont let it empty.

FLUTTER_APP_FLAVOR needs to be the value of the generated enum or the key of pubspec.yaml, in this example, "mynewapp" from mynewapp: