Storage items persist after uninstall on Android device

Current behavior

I’m using AsyncStorage for persisted storage. I noticed (while debugging an unrelated issue with Expo SecureStore) that the key/value pairs are persisting after I’ve uninstalled the app from my device.

I’ve tried the following:

• Ran ./gradlew clean in the android directory
• Rebuilt the android directory from scratch
• Removed all cache files and directories from the project (.gradle, .expo, etc)
• Used AsyncStorage.clear() and AsyncStorage.removeItem()
• Used storage analyzers to search for data (didn’t find anything)
• Manually removed storage and cache through Android Settings -> Apps & Notifications
• Uninstalled the app from the device
• Deleted Expo Go app and removed it’s storage and cache

It is my understanding that uninstalling the app should also remove persisted storage. However, this issue goes beyond this assumption if I am incorrect.

The items always show up after I uninstall and reinstall the app. Reloading the app does not have this same issue. I read through some old/closed issues here that showed others having this problem, with solutions that have not worked for me. Even after using AsyncStorage.clear() or AsyncStorage.removeItem(), the items will appear on every new install, but only after the app has been uninstalled from the device.

Expected behavior

After new installation or removing them, the storage items should no longer exist on the device.

Repro steps

1. Remove storage items with AsyncStorage.clear() or AsyncStorage.removeItem()
2. Delete app storage and cache in Android Settings -> Apps & Notifications
3. Uninstall the app from the device
4. Stop react-native
5. Run ./gradlew clean in the android directory
6. Start react-native with --reset-cache flag
7. Run react-native run-android to install the app

Environment

• Platforms tested:
  • Android
  • iOS
  • macOS
  • Windows
• AsyncStorage version: 1.14.1
• Expo version: SDK40 (bare workflow)
• Environment: System: OS: Linux 5.8 Pop!_OS 20.10 CPU: (8) x64 Intel® Core™ i7-8565U CPU @ 1.80GHz Memory: 12.40 GB / 31.08 GB Shell: 5.8 - /usr/bin/zsh Binaries: Node: 14.15.4 - ~/.nvm/versions/node/v14.15.4/bin/node Yarn: 1.22.10 - ~/.nvm/versions/node/v14.15.4/bin/yarn npm: 6.14.11 - ~/.nvm/versions/node/v14.15.4/bin/npm Watchman: Not Found (Watchman is global) SDKs: Android SDK: Not Found (it sure does, it’s in my home directory) IDEs: Android Studio: Not Found (not using android studio) Languages: Java: 11.0.10 - /usr/bin/javac Python: 2.7.18 - /usr/bin/python npmPackages: @react-native-community/cli: Not Found react: 16.13.1 => 16.13.1 react-native: ~0.63.4 => 0.63.4 npmGlobalPackages: react-native: Not Found (uses npx version)

[mdbiscan]

Looks like this setting in the AndroidManifest.xml file is on by default: android:allowBackup="true"

For future reference, this is the generated XML line from Expo:

  <application android:name=".MainApplication" android:label="@string/app_name" android:icon="@mipmap/ic_launcher" android:roundIcon="@mipmap/ic_launcher_round" android:allowBackup="true" android:theme="@style/AppTheme">

Setting this to false solves the issue. I’m not sure this is a good idea or not, as we also use keychain storage. I’m not sure if this backup feature also saves encrypted storage to the cloud.

Either way, thanks for pointing me in the right direction. I figured it might be some obtuse setting.

[Noitidart]

Hey @mdbiscan and @krizzu, does this apply to the Documents Directory pointed to by FileSystem.documentsDirectory? On iOS and Android?

I think I’m having some bugs due to this its just a hunch. I’m going to try to set that allowBackup to false in xml for Android, how could I do this for iOS?

Not using AsyncStorage but Expo filesystem - https://docs.expo.dev/versions/latest/sdk/filesystem/