Audit flutter for compatibility with the AGP 9.0.0 new dsl

[bc-lee]

As of today (2025-09-20), the Android Gradle Plugin (AGP) is at version 9.0.0-alpha05. This marks the first major release since AGP 8.0, which was introduced more than two years ago(2023-04).

According to the AGP Preview Release Notes, AGP 9.0.0 introduces a significant number of breaking changes. The Android community is still in the process of identifying migration strategies, with resources such as AGP Status Tracker documenting compatibility issues and workarounds.

Because Flutter supports a wide range of AGP versions, one key challenge will be ensuring compatibility. A likely near-term mitigation strategy is to apply:

android.newDsl=false

This would allow projects to defer adoption of the new DSL until much later in the AGP 9.x cycle (expected around next year), minimizing disruption while maintaining forward compatibility.

[reidbaker]

@jesswrd FYI, We have been working on Gradle 9 support let look into AGP 9 and see what work needs to be migrated.

@bc-lee Do you have a specific request here (like a flutter tool command that fails to work that we need to fix or having flutter add android.newDsl=false to project templates?) or were you filing an issue to let us know, which is still helpful.

[reidbaker]

related flutter/packages#10016

[bc-lee]

Do you have a specific request here (like a flutter tool command that fails to work that we need to fix or having flutter add android.newDsl=false to project templates?) or were you filing an issue to let us know, which is still helpful.

No, I just wanted to remind you of the incompatibilities so the Flutter team doesn’t forget. I suggested using android.newDsl=false since that seems like the easiest way to handle them, but it’s up to the Flutter Android team. 🙂

[reidbaker]

OK thank you for the issue. We will investigate if/where we break with the new dsl.

[AbdeMohlbi]

so after some debugging and testing , this is what i have found :
creating a project using flutter create and updating these build files :

• app/build.gradle.kts

plugins {
    id("com.android.application")
    id("kotlin-android")
    // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
    id("dev.flutter.flutter-gradle-plugin")
}

android {
    namespace = "com.example.demo_agp"
    compileSdk = flutter.compileSdkVersion
    ndkVersion = flutter.ndkVersion

    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_11
        targetCompatibility = JavaVersion.VERSION_11
    }

    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_11.toString()
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId = "com.example.demo_agp"
        // You can update the following values to match your application needs.
        // For more information, see: https://flutter.dev/to/review-gradle-config.
        minSdk = flutter.minSdkVersion
        targetSdk = flutter.targetSdkVersion
        versionCode = flutter.versionCode
        versionName = flutter.versionName
    }

    buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig = signingConfigs.getByName("debug")
        }
    }
}

flutter {
    source = "../.."
}

• gradle-wrapper.properties

distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-9.0.0-all.zip

• settings.gradle.kts

pluginManagement {
    val flutterSdkPath =
        run {
            val properties = java.util.Properties()
            file("local.properties").inputStream().use { properties.load(it) }
            val flutterSdkPath = properties.getProperty("flutter.sdk")
            require(flutterSdkPath != null) { "flutter.sdk not set in local.properties" }
            flutterSdkPath
        }

    includeBuild("$flutterSdkPath/packages/flutter_tools/gradle")

    repositories {
        google()
        mavenCentral()
        gradlePluginPortal()
    }
}

plugins {
    id("dev.flutter.flutter-plugin-loader") version "1.0.0"
    id("com.android.application") version "9.0.0-alpha05" apply false
    id ("org.jetbrains.kotlin.android") version "2.2.10" apply false
}

include(":app")

will result the build o fail with the error :

Build file 'C:\Users\Abdessalem\Desktop\demo_agp\android\app\build.gradle.kts' line: 1

An exception occurred applying plugin request [id: 'kotlin-android']
> Failed to apply plugin 'kotlin-android'.
   > Cannot add extension with name 'kotlin', as there is an extension already registered with that name.

* Try:
> Run with --info or --debug option to get more log output.
> Run with --scan to generate a Build Scan (Powered by Develocity).
> Get more help at https://help.gradle.org.

which is expected because according to the link given by OP Switch to [built-in Kotlin](https://developer.android.com/build/releases/agp-preview#android-gradle-plugin-built-in-kotlin): The org.jetbrains.kotlin.android plugin is not compatible with the new DSL. which means that id("kotlin-android") in app/build.gradle.kts should be removed but when doing that will break the FGP because // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins. with the error:

An exception occurred applying plugin request [id: 'dev.flutter.flutter-gradle-plugin']
> Failed to apply plugin 'dev.flutter.flutter-gradle-plugin'.
   > java.lang.NullPointerException (no error message)

another issue is that AGP 9 introduced breaking changes for some API , the most important and related to our current issue being ApkVariant and here is the lint that appears 'interface ApkVariant : BaseVariant, InstallableVariant, AndroidArtifactVariant, InternalBaseVariant' is deprecated. Deprecated in Java. , here is the lint from android studio:

so apparently issue 166550 needs to be fixed before moving forward on this, there are other changes to to other APIs like ApplicationExtension which we currently use but it seems a bit simpler then the first one .

for the opt out :

adding android.newDsl=false to gradle.properties file and removing this bloc from app/build.gradle.kts:

kotlinOptions {
    jvmTarget = JavaVersion.VERSION_11.toString()
}

results another error: The project is using an incompatible version (AGP 9.0.0-alpha05) of the Android Gradle plugin. Latest supported version is AGP 8.13.0 which is more confusing because i was able to start some tasks before with AGP 9.0.0-alpha05 but now it fails the moment i start any task.
after doing what android studio suggests and using AGP 8.13.0 the app starts as expected
CC @reidbaker

[bc-lee]

results another error: The project is using an incompatible version (AGP 9.0.0-alpha05) of the Android Gradle plugin. Latest supported version is AGP 8.13.0

This error indicates a mismatch between your AGP version and your Android Studio version. You can still build using the Gradle CLI.

If you want to use an AGP alpha version, you also need to use the corresponding Canary build of Android Studio. For example, the latest AGP 9.0.0-alpha06 is only compatible with Android Studio Otter | 2025.2.1 Canary 1, which was released on 2025-09-22 (just two days ago).