[Bug]: AGP 9 incompatibility — kotlin-android plugin must be removed

[dbebawy]

Description

The wakelock_plus plugin applies the kotlin-android plugin in its android/build.gradle. Starting with AGP 9.0.0, built-in Kotlin is the default and applying the kotlin-android plugin causes a build failure:

Failed to apply plugin 'kotlin-android'.
> ⛔ Failed to apply plugin 'org.jetbrains.kotlin.android'
  The 'org.jetbrains.kotlin.android' plugin is no longer required for Kotlin support since AGP 9.0.
  Solution: Remove the 'org.jetbrains.kotlin.android' plugin from this project's build file.

Steps to reproduce

1. Create or migrate a Flutter project to AGP 9.0.0 following https://docs.flutter.dev/release/breaking-changes/migrate-to-agp-9
2. Add wakelock_plus as a dependency
3. Run flutter build apk --debug
4. Build fails with the error above

Current workaround

Set android.builtInKotlin=false in gradle.properties and re-add the kotlin-android plugin to the app's build.gradle. This is a temporary escape hatch that will be removed before AGP 10.0.

Expected fix

Remove id("kotlin-android") from the plugin's android/build.gradle — AGP 9's built-in Kotlin handles Kotlin compilation without a separate plugin.

Environment

• wakelock_plus: 1.4.0
• Flutter: 3.38.9
• Dart: 3.10.8
• AGP: 9.0.0
• Gradle: 9.3.1

Related issues

• Flutter tracking: [many] Flutter maintained plugins should support AGP 9.0 flutter/flutter#181383
• Flutter migration guide: https://docs.flutter.dev/release/breaking-changes/migrate-to-agp-9
• Similar issue on plus_plugins: [Compile]: The 'org.jetbrains.kotlin.android' plugin is no longer required for Kotlin support since AGP 9.0 plus_plugins#3745

[diegotori]

@dbebawy this is gonna have to wait until there's a surefire way to migrate Flutter Plugins to AGP 9.0.

Once the Flutter Team posts an official migration path, then this library will certainly get migrated over.

[under3415]

Flutter has posted this migration guide: https://docs.flutter.dev/release/breaking-changes/migrate-to-built-in-kotlin/for-plugin-authors

We are getting below warnings on build:

WARNING: Your app uses the following plugins that apply Kotlin Gradle Plugin (KGP): wakelock_plus

Future versions of Flutter will fail to build if your app uses plugins that apply KGP.

Please check the changelogs of these plugins and upgrade to a version that supports Built-in Kotlin.
If no such version exists, report the issue to the plugin. If necessary, here is a guide on filing
an issue against a plugin: https://docs.flutter.dev/release/breaking-changes/migrate-to-built-in-kotlin/for-app-developers#report-incompatible-kotlin-gradle-plugin-usage-to-plugin-authors

If you are a plugin author, please migrate your plugin to Built-in Kotlin using this guide: https://docs.flutter.dev/release/breaking-changes/migrate-to-built-in-kotlin/for-plugin-authors