[Android] Misleading message when loadLibrary throws UnsatisfiedLinkError with app bundle #168272
Description
Steps to reproduce
Description
When an app is published as an Android App Bundle, errors occasionally occur during native-library loading (see #151638 (comment), #151638 (comment) and related comments).
The primary problem resides in this code block, which builds a human-readable error message:
When running from a bundle, this log often shows:
App is using cpu architecture: aarch64, and the native libraries directory (with path /data/app/~~2UHRMKRY95HcmDUp4LaWNw==/za.co.clock.africlock-rUsnC1k6b87NW4W_Hk48kg==/lib/arm64) contains the following files: null
In fact, bundles can split native libraries across multiple directories. If you install the APKs generated by Bundletool (without useLegacyPackaging), the needed library may be in a different “split” directory.
Current Lookup Logic
The Flutter embedding lists native-library directories using only
This is insufficient to enumerate every possible library location.
Possible fix
When building bundle and installing apk created out of this bundle with bundletool there is line in logs which describes path where native libs might be stored on device:
Configuring clns-7 for other apk /data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/base.apk:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.arm64_v8a.apk:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.en.apk:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.xxhdpi.apk. target_sdk_version=35, uses_libraries=, library_path=/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/lib/arm64:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/base.apk!/lib/arm64-v8a:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.arm64_v8a.apk!/lib/arm64-v8a:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.en.apk!/lib/arm64-v8a:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg=
library_path is constructed from each split of app. Later, the loader logs exactly from which split it loads libflutter.so:
Load /data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.arm64_v8a.apk!/lib/arm64-v8a/libflutter.so using ns clns-7 from class loader (caller=/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/base.apk): ok
split_config.arm64_v8a.apk is the third dir in the path.
Main proposal here is to use not only nativeLibraryDir, but also all splitSourceDirs and construct paths where libraries might exist from them.
This change will produce a clear, comprehensive list of all inspected directories/APKs, making it easier to diagnose why a particular native library failed to load on split-APK installations.
Maybe it'll even help with investigation on #151638
Expected results
Correct UnsupportedOperationException with full list of possible locations of native libraries and its content.
Actual results
Only single base nativeLibsDir is listed which leads to null instead of list with available libraries.
Code sample
I created a simple project here: https://github.com/Sameri11/misleading_jni_libs_error
In the MainActivity.kt there is code which tries to construct library_paths from splitSourceDirs and print to log. This constructed path is the same as the path reported from native loader.
Make sure that project is built with flutter build appbundle and installed with bundletool. Detailed description is in Readme.
Screenshots or Video
Screenshots / Video demonstration
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Logs
Logs
4 lines
First and second are from native loader itself.
Third and fourth lines are from MainActivity.kt. Third line reports contents of nativeLibsDir alone.
Fourth line reports result of the code which compiles path from nativeLibsDir and splitSourceDirs.
2025-05-03 20:19:40.770 29789-29789 nativeloader com.example.app_test D Configuring clns-7 for other apk /data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/base.apk:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.arm64_v8a.apk:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.en.apk:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.xxhdpi.apk. target_sdk_version=35, uses_libraries=, library_path=/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/lib/arm64:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/base.apk!/lib/arm64-v8a:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.arm64_v8a.apk!/lib/arm64-v8a:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.en.apk!/lib/arm64-v8a:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg=
2025-05-03 20:19:40.862 29789-29808 nativeloader com.example.app_test D Load /data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.arm64_v8a.apk!/lib/arm64-v8a/libflutter.so using ns clns-7 from class loader (caller=/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/base.apk): ok
2025-05-03 20:19:41.439 29789-29789 nativeloader com.example.app_test D Native Library Path: /data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/lib/arm64
2025-05-03 20:19:41.453 29789-29789 nativeLoader com.example.app_test D Load library path: /data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/lib/arm64:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/base.apk!/lib/arm64-v8a:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.arm64_v8a.apk!/lib/arm64-v8a:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.en.apk!/lib/arm64-v8a:/data/app/~~9xW4-yMGyelaPI4JoU8LUg==/com.example.app_test-TLMiWr6lcykuU_hY70C7mg==/split_config.xxhdpi.apk!/lib/arm64-v8aFlutter Doctor output
Doctor output
flutter doctor -v
[✓] Flutter (Channel master, 3.32.0-1.0.pre.397, on macOS 14.7 23H124 darwin-arm64, locale en-RU) [5.2s]
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