Unable to load dynamic library with FFI on some devices

[jaween]

My Flutter app distributed on the Google Play store seems to be unable to load a packaged dynamic library on a few devices. They are ARM devices I believe, and the APK distributed to those devices do seem to contain the libraster.so library (built and packaged using Cmake/NDK. It is difficult for me to test this as I don't have these particular devices to try to reproduce the test on.

Steps to Reproduce

1. Create a Flutter app that packages in an NDK built library
2. Run the app on one of the devices listed below
3. Load the library at runtime in Flutter using the FFI
4. Experience an ArgumentException

Expected results:
The library is loaded successfully.

Actual results:
The library is unable to be found and so can not be loaded with the following error:

ArgumentException
 Invalid argument(s): Failed to load dynamic library (dlopen failed: library "libraster.so" not found)

Affected devices

Model	Name	Android version
SM-G928F	Samsung Galaxy S6 Edge+	6.0.1
SM-J500M	Samsung Galaxy J5	6.0.1
SM-J710GN	Samsung Galaxy J7 2016	6.0.1
SM-T110	Samsung Galaxy Tab 3 Lite 7.0	4.2.2
SM-T111M	Samsung Galaxy Tab 3 Lite 7.0	4.2.2
GT-I8262	Samsung Galaxy Core Duos	4.1.2
GT-I8552	Samsung Galaxy Win Duos	4.1.2
GT-I8552B	Samsung Galaxy Win Duos	4.1.2
GT-I9082L	Samsung Galaxy Grand Duos	4.2.2
GT-I9300	Samsung Galaxy S III	4.1.2
GT-N8000	Samsung Galaxy Note 10.1	4.1.2
GT-N8010	Samsung Galaxy Note 10.1	4.1.2
GT-P3110	Samsung Galaxy Tab 2 7.0	4.1.2
GT-P5110	Samsung Galaxy Tab 2 10.1	4.2.2
SO-03E	Sony Xperia Tablet Z	4.1.2
B1-A71	Acer Iconia Tab B1-A71	4.1.2
F-01F	Fujitsu Arrows NX F-01F	4.2.2
ME173X	Asus Memo Pad HD7	4.2.2

Since the library does load successfully on many other devices, I'm unsure what the cause of this could be. Assuming this is a Dart/Flutter related issue, I have excluded some details of my Gradle build here. There are more details on my StackOverflow question.

Flutter doctor output

flutter doctor --verbose
[✓] Flutter (Channel stable, 1.22.5, on Linux, locale en_AU.UTF-8)
    • Flutter version 1.22.5 at /opt/flutter
    • Framework revision 7891006299 (4 weeks ago), 2020-12-10 11:54:40 -0800
    • Engine revision ae90085a84
    • Dart version 2.10.4

 
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
    • Android SDK at /home/jaween/Android/Sdk
    • Platform android-30, build-tools 29.0.3
    • Java binary at: /opt/android-studio/jre/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[!] Android Studio
    • Android Studio at /opt/android-studio
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] Connected device (1 available)
    • SM A520F (mobile) • 5200676a4a815579 • android-arm64 • Android 8.0.0 (API 26)

[dcharkes]

We also have other users reporting issues with Android <= 6. Though, we've not been able to pinpoint a solution.

Possible workarounds:

• [shared_preferences] Plugin project :shared_preferences_web not found. Please update settings.gradle. #55827 (comment) Tweak Gradle files.
• dart:ffi conflicts with System.loadLibrary on Android API <=23 #59834 Call dlopen very early, outside Dart:

/**
 * The loader for the X native library.
 *
 * This plugin is purely a workaround. On API versions <=23, it is possible to
 * call an Android SDK method that loads a native library that changes the paths searched when
 * `DynamicLibrary.open` is called in Dart.
 *
 * As such, this plugin is configured to load the shared library when it is registered, so that
 * when `DynamicLibrary.open('libX.so')` is called subsequently through Dart, it will be a
 * no-op.
 */
public final class XLoader implements FlutterPlugin {
  @Override
  public void onAttachedToEngine(@NonNull FlutterPluginBinding binding) {
    loadLibrary();
  }

  @Override
  public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {}

  private static boolean isLibraryLoaded = false;

  private static void loadLibrary() {
    if (isLibraryLoaded) {
      return;
    }

    // Loads `libX.so`.
    System.loadLibrary("X");
    isLibraryLoaded = true;
  }
}

[jaween]

@dcharkes Thank you for your helpful answer.

I have now implemented the second workaround that you suggested (calling dlopen early outside Dart). It does indeed seem to have fixed the issue for the affected devices.

My specific problem is now solved, so I will close this issue. From what I understand Dart SDK issue #37771 and Flutter issue #59834 address the cause of the problem, so when those issues are solved, this workaround can be removed from the application.

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.