UninitializedPropertyAccessException crash on Android when amplify_datastore is included but not used

[giulitu95]

Description

We're observing a crash on Android devices only (iOS is unaffected) when the amplify_datastore package is included in the project, but no Amplify functionality is used at runtime.

In our case, we temporarily released our app without using any Amplify features, although the library was still present in pubspec.yaml.

This results in a runtime crash due to an uninitialized lateinit property, even though the plugin is never used or initialized in code.

Root cause

The issue originates from the DataStoreHubEventStreamHandler.kt file:

• The token variable is declared as lateinit:

amplify-flutter/packages/amplify_datastore/android/src/main/kotlin/com/amazonaws/amplify/amplify_datastore/DataStoreHubEventStreamHandler.kt

Line 36 in 1b9155e

private lateinit var token: SubscriptionToken

• It is accessed in the onCancel() method:

amplify-flutter/packages/amplify_datastore/android/src/main/kotlin/com/amazonaws/amplify/amplify_datastore/DataStoreHubEventStreamHandler.kt

Lines 224 to 227 in 1b9155e

	override fun onCancel(p0: Any?) {
	eventSink = null
	Amplify.Hub.unsubscribe(token)
	}

This method gets triggered by the Flutter engine even though the stream wasn't properly initialized — because no Amplify plugin was ever added or configured.

More specifically, the stream gets initialized only when the AmplifyDataStore plugin is added via Amplify.addPlugin(...), which internally sets up the static streamWrapper and assigns a DataStoreStreamController. When this step is skipped (as in our case), the token remains uninitialized, and accessing it during onCancel() causes the app to crash.

Expected behavior

Including the amplify_datastore package without using it should not crash the app.
The plugin should:

• Either check whether token is initialized using ::token.isInitialized before accessing it.

• Or register/deregister the EventChannel only when the plugin is fully configured.

Sentry stacktrace

java.lang.RuntimeException: Unable to destroy activity {com.faegroup.app/com.faegroup.app.MainActivity}: kotlin.UninitializedPropertyAccessException: lateinit property token has not been initialized
    at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:5654)
    at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:5687)
    at android.app.servertransaction.DestroyActivityItem.execute(DestroyActivityItem.java:47)
    at android.app.servertransaction.ActivityTransactionItem.execute(ActivityTransactionItem.java:45)
    at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:176)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2374)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loopOnce(Looper.java:233)
    at android.os.Looper.loop(Looper.java:344)
    at android.app.ActivityThread.main(ActivityThread.java:8249)
    at java.lang.reflect.Method.invoke(Method.java)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:589)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1071)
kotlin.UninitializedPropertyAccessException: lateinit property token has not been initialized
    at com.amazonaws.amplify.amplify_datastore.DataStoreHubEventStreamHandler.onCancel(DataStoreHubEventStreamHandler.kt:226)
    at com.amazonaws.amplify.amplify_datastore.AmplifyDataStorePlugin.onDetachedFromEngine(AmplifyDataStorePlugin.kt:195)
    at io.flutter.embedding.engine.FlutterEngineConnectionRegistry.remove(FlutterEngineConnectionRegistry.java:272)
    at io.flutter.embedding.engine.FlutterEngineConnectionRegistry.remove(FlutterEngineConnectionRegistry.java:280)
    at io.flutter.embedding.engine.FlutterEngineConnectionRegistry.removeAll(FlutterEngineConnectionRegistry.java:288)
    at io.flutter.embedding.engine.FlutterEngineConnectionRegistry.destroy(FlutterEngineConnectionRegistry.java:123)
    at io.flutter.embedding.engine.FlutterEngine.destroy(FlutterEngine.java:473)
    at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.onDetach(FlutterActivityAndFragmentDelegate.java:772)
    at io.flutter.embedding.android.FlutterActivity.onDestroy(FlutterActivity.java:909)
    at android.app.Activity.performDestroy(Activity.java:8406)
    at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1378)
    at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:5641)
    at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:5687)
    at android.app.servertransaction.DestroyActivityItem.execute(DestroyActivityItem.java:47)
    at android.app.servertransaction.ActivityTransactionItem.execute(ActivityTransactionItem.java:45)
    at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:176)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2374)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loopOnce(Looper.java:233)
    at android.os.Looper.loop(Looper.java:344)
    at android.app.ActivityThread.main(ActivityThread.java:8249)
    at java.lang.reflect.Method.invoke(Method.java)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:589)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1071)

Categories

• Analytics
• API (REST)
• API (GraphQL)
• Auth
• Authenticator
• DataStore
• Notifications (Push)
• Storage

Steps to Reproduce

1. Add the amplify_datastore package to a Flutter project (via pubspec.yaml).
2. Do not call Amplify.addPlugin() with AmplifyDataStore, and do not interact with Amplify in any way.
3. Run the app on an Android device.

Screenshots

No response

Platforms

• iOS
• Android
• Web
• macOS
• Windows
• Linux

Flutter Version

3.29.2

Amplify Flutter Version

2.6.1

Deployment Method

Amplify CLI (Gen 1)

Schema

[ekjotmultani]

Hi @giulitu95, this is very strange, I'm sorry you are facing this. I'll try to reproduce this and get back to you

[tyllark]

Hello @giulitu95, I agree that just adding the DataStore package should not cause any exceptions or crashes so we will mark this as a bug. In the meantime you seem to have a work around of not including DataStore in your pubspec.yaml while you are not using it.

however I've been unable to reproduce the issue on my end despite verifying amplify_datastore is present in my pubspec.lock file and not referencing Amplify with my code. Do you have any addition reproduction steps or a minimal reproducible example?

  amplify_datastore:
    dependency: "direct main"
    description:
      name: amplify_datastore
      sha256: "8c9555e0ae12e3d1bf55cb7b248fb2dbfd3594fa19ac60a1ae88554b06709b95"
      url: "https://pub.dev"
    source: hosted
    version: "2.6.1"

[tyllark]

Hello @giulitu95, are you still experiencing this issue, if so could you please provide a minimal reproducible example.