audio_session not compatible with AGP9+

[under3415]

Since upgrading to Gradle 9.3.1 and AGP 9.0 cannot build due to audio_session issue

FAILURE: Build completed with 2 failures.

1: Task failed with an exception.
-----------
* Where:
Build file 'C:\Users\dejan\AppData\Local\Pub\Cache\hosted\pub.dev\audio_session-0.2.2\android\build.gradle' line: 33

* What went wrong:
A problem occurred evaluating project ':audio_session'.
> 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: ..\..\..\..\Users\dejan\AppData\Local\Pub\Cache\hosted\pub.dev\audio_session-0.2.2\android\build.gradle.
     See https://kotl.in/gradle/agp-built-in-kotlin for more details.
      > java.lang.Throwable (no error message)

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights from a Build Scan (powered by Develocity).
> Get more help at https://help.gradle.org.
==============================================================================

┌─ Flutter Fix ────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ [!] Starting AGP 9+, the default has become built-in Kotlin. This results in a build failure when applying the kotlin-android plugin at                  │
│ C:\src\projects\project\android\app\build.gradle.                                                                                                │
│                                                                                                                                                          │
│ To resolve this, migrate to built-in Kotlin. For instructions on how to migrate, see: https://docs.flutter.dev/release/breaking-changes/migrate-to-agp-9 │
└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
Gradle task bundleRelease failed with exit code 1`

Flutter Doctor:

[√] Flutter (Channel stable, 3.38.9, on Microsoft Windows [Version 10.0.26200.7705], locale en-NZ) [626ms]
    • Flutter version 3.38.9 on channel stable at C:\src\flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 67323de285 (3 days ago), 2026-01-28 13:43:12 -0800
    • Engine revision 587c18f873
    • Dart version 3.10.8
    • DevTools version 2.51.1
    • Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop, enable-android, enable-ios, cli-animations, enable-native-assets,
      omit-legacy-version-file, enable-lldb-debugging

[√] Windows Version (11 Pro 64-bit, 25H2, 2009) [1,374ms]

[√] Android toolchain - develop for Android devices (Android SDK version 36.1.0) [3.8s]
    • Android SDK at C:\Users\dejan\AppData\Local\Android\sdk
    • Emulator version 36.3.10.0 (build_id 14472402) (CL:N/A)
    • Platform android-36.1, build-tools 36.1.0
    • Java binary at: C:\Program Files\Android\Android Studio\jbr\bin\java
      This is the JDK bundled with the latest Android Studio installation on this machine.
      To manually set the JDK path, use: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version OpenJDK Runtime Environment (build 21.0.8+-14196175-b1038.72)
    • All Android licenses accepted.

[under3415]

I forked it here to resolve this: https://github.com/under3415/audio_session

[ryanheise]

@under3415 Please consider submitting a pull request so that a fix can be tied into the ecosystem. You can follow the same instructions from the just_audio pull request instructions:

https://github.com/ryanheise/just_audio/blob/minor/CONTRIBUTING.md

[under3415]

Seems this is on hold for now...

From https://blog.flutter.dev/whats-new-in-flutter-3-41-302ec140e632

Android Grade Plugin (AGP) 9 and Kotlin DSL

We continue to align with modern Android standards. With the release of Android Gradle Plugin (AGP) 9, we are working on supporting new strictness requirements and providing guidance on how to navigate them.

Warning: Do not update your Flutter app for Android to AGP 9 as migrating plugins to AGP 9 and Flutter apps on AGP 9 using plugins is not yet supported (#181383). This support is paused while the Flutter team audits the migration for backwards compatibility with older versions of AGP. This migration doc will be updated as guidance changes.

Thanks to contributions from community member Byoungchan Lee (bc-lee@), new plugin projects now default to using the Kotlin DSL for Gradle.