Zenn
Galirage Inc.
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Shrinker Java Bytecodeのバグ対処法【Flutter / Dart / Android】

ますみ / 生成AIエンジニア
2021/10/02に公開
Android
Flutter
Dart
tech

はじめまして、ますみです！

株式会社Galirage（ガリレージ）という「生成AIに特化して、システム開発・アドバイザリー支援・研修支援をしているIT企業」で、代表をしております^^

自己紹介.png

FlutterでのiOS開発を進めている中、ある日Androidのビルドをしたところ、Shrinker Java Bytecodeのエラーにつまづいてしまいました。
flutter run、flutter build bundle、flutter build apk、flutter build appbundleなどのandroidのビルドをする際に最初につまづく部分だと思います。
そこで、この記事では、このエラーの対処法を解説します。

エラー内容

main_error
FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:mergeDexDebug'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.Workers$ActionFacade
   > com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
     The number of method references in a .dex file cannot exceed 64K.
     Learn how to resolve this issue at https://developer.android.com/tools/building/multidex.html

* 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.

* Get more help at https://help.gradle.org

BUILD FAILED in 8s
[!] The shrinker may have failed to optimize the Java bytecode.
    To disable the shrinker, pass the `--no-shrink` flag to this command.
    To learn more, see: https://developer.android.com/studio/build/shrink-code
Exception: Gradle task assembleDebug failed with exit code 1
エラー全文はこちら
error_all
D8: Cannot fit requested classes in a single dex file (# methods: 89373 > 65536)
com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
The number of method references in a .dex file cannot exceed 64K.
Learn how to resolve this issue at https://developer.android.com/tools/building/multidex.html
 at com.android.builder.dexing.D8DexArchiveMerger.getExceptionToRethrow(D8DexArchiveMerger.java:132)
 at com.android.builder.dexing.D8DexArchiveMerger.mergeDexArchives(D8DexArchiveMerger.java:119)
 at com.android.build.gradle.internal.transforms.DexMergerTransformCallable.call(DexMergerTransformCallable.java:102)
 at com.android.build.gradle.internal.tasks.DexMergingTaskRunnable.run(DexMergingTask.kt:432)
 at com.android.build.gradle.internal.tasks.Workers$ActionFacade.run(Workers.kt:242)
 at org.gradle.workers.internal.AdapterWorkAction.execute(AdapterWorkAction.java:57)
 at org.gradle.workers.internal.DefaultWorkerServer.execute(DefaultWorkerServer.java:63)
 at org.gradle.workers.internal.NoIsolationWorkerFactory$1$1.create(NoIsolationWorkerFactory.java:67)
 at org.gradle.workers.internal.NoIsolationWorkerFactory$1$1.create(NoIsolationWorkerFactory.java:63)
 at org.gradle.internal.classloader.ClassLoaderUtils.executeInClassloader(ClassLoaderUtils.java:97)
 at org.gradle.workers.internal.NoIsolationWorkerFactory$1.lambda$execute$0(NoIsolationWorkerFactory.java:63)
 at org.gradle.workers.internal.AbstractWorker$1.call(AbstractWorker.java:44)
 at org.gradle.workers.internal.AbstractWorker$1.call(AbstractWorker.java:41)
 at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:200)
 at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:195)
 at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:75)
 at org.gradle.internal.operations.DefaultBuildOperationRunner$3.execute(DefaultBuildOperationRunner.java:68)
 at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:153)
 at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:68)
 at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:62)
 at org.gradle.internal.operations.DefaultBuildOperationExecutor.lambda$call$2(DefaultBuildOperationExecutor.java:76)
 at org.gradle.internal.operations.UnmanagedBuildOperationWrapper.callWithUnmanagedSupport(UnmanagedBuildOperationWrapper.java:54)
 at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:76)
 at org.gradle.workers.internal.AbstractWorker.executeWrappedInBuildOperation(AbstractWorker.java:41)
 at org.gradle.workers.internal.NoIsolationWorkerFactory$1.execute(NoIsolationWorkerFactory.java:60)
 at org.gradle.workers.internal.DefaultWorkerExecutor.lambda$submitWork$2(DefaultWorkerExecutor.java:200)
 at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
 at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.runExecution(DefaultConditionalExecutionQueue.java:215)
 at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.runBatch(DefaultConditionalExecutionQueue.java:164)
 at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.run(DefaultConditionalExecutionQueue.java:131)
 at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
 at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
 at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
 at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
 at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
 at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
 at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
 at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: com.android.tools.r8.CompilationFailedException: Compilation failed to complete, position: null
 at Version.fakeStackEntry(Version_2.1.62.java:0)
 at com.android.tools.r8.utils.Y.a(SourceFile:78)
 at com.android.tools.r8.D8.run(D8.java:11)
 at com.android.builder.dexing.D8DexArchiveMerger.mergeDexArchives(D8DexArchiveMerger.java:117)
 ... 36 more
Caused by: com.android.tools.r8.utils.b: Cannot fit requested classes in a single dex file (# methods: 89373 > 65536)
 at com.android.tools.r8.utils.T0.error(SourceFile:1)
 at com.android.tools.r8.utils.T0.a(SourceFile:2)
 at com.android.tools.r8.dex.P.a(SourceFile:740)
 at com.android.tools.r8.dex.P$h.a(SourceFile:7)
 at com.android.tools.r8.dex.b.a(SourceFile:14)
 at com.android.tools.r8.dex.b.b(SourceFile:25)
 at com.android.tools.r8.D8.d(D8.java:133)
 at com.android.tools.r8.D8.b(D8.java:1)
 at com.android.tools.r8.utils.Y.a(SourceFile:36)
 ... 38 more


FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:mergeDexDebug'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.Workers$ActionFacade
   > com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
     The number of method references in a .dex file cannot exceed 64K.
     Learn how to resolve this issue at https://developer.android.com/tools/building/multidex.html

* 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.

* Get more help at https://help.gradle.org

BUILD FAILED in 8s
[!] The shrinker may have failed to optimize the Java bytecode.
    To disable the shrinker, pass the `--no-shrink` flag to this command.
    To learn more, see: https://developer.android.com/studio/build/shrink-code
Exception: Gradle task assembleDebug failed with exit code 1
  • このエラーは簡単にいうと「ビルド時の中間ファイルを最適化するときに生じているバグ」です。

対処法

  • minSdkVersionをバージョンを上げると直りました。
  • もしもここをどうしても変えたくない場合は、flutter run --no-shrinkというオプションをつけてもいいですが、minSdkVersion: 16は2012年のJELLY_BEANの時代のものなため、さすがにリガシーバージョンと捉えて、deprecated（非推奨バージョン）として良いと思います（ここはチームの開発指針次第）。
  • 私は、Android 5.0（sdkVersion: 21、LOLLIPOP、2015年）が一つのメジャーアップデートの区切れ目なので、そこまで引き上げることを推奨します（下記コード参照）。
android/app/build.gradle
defaultConfig {
    // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
    applicationId "dev.umimori.sample"
-   minSdkVersion 16
+   minSdkVersion 21
    targetSdkVersion 30
    versionCode flutterVersionCode.toInteger()
    versionName flutterVersionName
}
  • APIレベル表も参考として載せておきます。

https://developer.android.com/guide/topics/manifest/uses-sdk-element?hl=ja#ApiLevels

最後に

最後まで読んでくださり、ありがとうございました！
この記事を通して、少しでもあなたの学びに役立てば幸いです！

宣伝：もしもよかったらご覧ください^^

『AIとコミュニケーションする技術（インプレス出版）』という書籍を出版しました🎉

これからの未来において「変わらない知識」を見極めて、生成AIの業界において、読まれ続ける「バイブル」となる本をまとめ上げました。

かなり自信のある一冊なため、もしもよろしければ、ご一読いただけますと幸いです^^

Galirage Inc.
Galirage Inc.

株式会社Galirageのテックブログです！ Galirageでは、生成AIのシステム開発・コンサルティング・研修を行なっております。 ▼ 問い合わせ先 ▼ info@galirage.com

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