Failed to load PDFium module: Exception: Native assets file not found.

[test0terter0n]

After upgrading to latest version, our integration tests are failing during execution. We use firebase test lab to tu run our integration tests. Last working version was pdfrx: ^2.2.24.
I guess issue might be related to 'Updated native PDFium binaries to chromium/7811.' from Version 2.3.0.

We build our app for the integration test like this:
flutter build apk --debug --flavor $BUILD_FLAVOR --dart-define=APP_FLAVOR=$APP_FLAVOR
To create debug and test Apk:

DART_DEFINES="$(printf "APP_FLAVOR=$APP_FLAVOR" | base64)"
./gradlew app:assembleAndroidTest -Pdart-defines="$DART_DEFINES"
./gradlew app:assembleDebug -Ptarget="$APP_DIR/integration_test/main.dart" -Pdart-defines="$DART_DEFINES"

To run the tests we do:
gcloud firebase test android run firebase_test_lab_config.yaml

In the logcat I see:

05-11 22:13:11.136 22145 22381 E flutter : [ERROR:flutter/runtime/dart_isolate.cc(1402)] Unhandled exception:
05-11 22:13:11.136 22145 22381 E flutter : Exception: Failed to load PDFium module: Exception: Native assets file not found.
05-11 22:13:11.136 22145 22381 E flutter : #0      getPdfium (package:pdfium_dart/src/pdfium_loader.dart:31:5)
05-11 22:13:11.136 22145 22381 E flutter : #1      pdfium (package:pdfrx_engine/src/native/pdfium.dart:11:31)
05-11 22:13:11.136 22145 22381 E flutter : #2      _init.<anonymous closure>.<anonymous closure> (package:pdfrx_engine/src/native/pdfrx_pdfium.dart:52:7)
05-11 22:13:11.136 22145 22381 E flutter : #3      _ExecuteParams.execute (package:pdfrx_engine/src/native/worker.dart:166:43)
05-11 22:13:11.136 22145 22381 E flutter : #4      BackgroundWorker._workerEntry.<anonymous closure> (package:pdfrx_engine/src/native/worker.dart:80:19)
05-11 22:13:11.136 22145 22381 E flutter : #5      _RootZone.runUnaryGuarded (dart:async/zone.dart:891:10)
05-11 22:13:11.136 22145 22381 E flutter : #6      _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:381:11)
05-11 22:13:11.136 22145 22381 E flutter : #7      _BufferingStreamSubscription._add (dart:async/stream_impl.dart:312:7)
05-11 22:13:11.136 22145 22381 E flutter : #8      _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:798:19)
05-11 22:13:11.136 22145 22381 E flutter : #9      _StreamController._add (dart:async/stream_controller.dart:663:7)
05-11 22:13:11.136 22145 22381 E flutter : #10     _StreamController.add (dart:async/stream_controller.dart:618:5)

After this error, our test is stuck and won't even start and times out.

Any ideas how to fix this?

[espresso3389]

I investigated this on the current master with Flutter 3.41.8.

What I checked locally:

• flutter build apk --debug for the pdfrx example app
• direct Gradle build similar to the reported flow:

JAVA_HOME=/Applications/Android\ Studio.app/Contents/jbr/Contents/Home \
  ./gradlew app:assembleDebug -Ptarget=lib/main.dart

In both cases, the generated app APK contained PDFium native libraries:

lib/arm64-v8a/libpdfium.so
lib/armeabi-v7a/libpdfium.so
lib/x86_64/libpdfium.so
assets/flutter_assets/NativeAssetsManifest.json

The generated NativeAssetsManifest.json looked like this:

{"format-version":[1,0,0],"native-assets":{"android_arm":{"package:pdfium_dart/libpdfium":["absolute","libpdfium.so"]},"android_arm64":{"package:pdfium_dart/libpdfium":["absolute","libpdfium.so"]},"android_x64":{"package:pdfium_dart/libpdfium":["absolute","libpdfium.so"]}}}

I also checked assembleAndroidTest. The androidTest APK itself does not contain libpdfium.so, but that seems expected because the Flutter app code and its native libraries are packaged in the app APK, not in the test APK.

One important detail: the reported Native assets file not found is probably a secondary error. On Android, pdfium_dart first tries:

DynamicLibrary.open('libpdfium.so')

If that fails, it falls back to looking for .dart_tool/native_assets.yaml. That file is not present inside a Flutter Android app at runtime, so the fallback hides the original dlopen failure reason.

Could you check the exact app APK that is uploaded to Firebase Test Lab with these commands?

unzip -l path/to/app-debug.apk | grep libpdfium.so
unzip -p path/to/app-debug.apk assets/flutter_assets/NativeAssetsManifest.json

If your project uses flavors, please also verify that the APK uploaded to Firebase Test Lab is the flavor-specific app APK generated by the same build variant that includes the integration-test target. Also check whether your Android config has abiFilters or splits that might omit the ABI used by the Test Lab device.

Separately, I think we should improve the PDFium loader diagnostics so that the original DynamicLibrary.open('libpdfium.so') error is preserved when the fallback also fails. That should make the next failure report much easier to diagnose.

Written by Codex

[test0terter0n]

Hey @espresso3389 , thanks for your fast response.

unzip -l path/to/app-debug.apk | grep libpdfium.so
gives me:

  4209140  01-01-1981 01:01   lib/arm64-v8a/libpdfium.so
  4209140  01-01-1981 01:01   lib/armeabi-v7a/libpdfium.so
  4209140  01-01-1981 01:01   lib/x86_64/libpdfium.so

unzip -p path/to/app-debug.apk assets/flutter_assets/NativeAssetsManifest.json
gives me:
{"format-version":[1,0,0],"native-assets":{"android_arm":{"package:pdfium_dart/libpdfium":["absolute","libpdfium.so"],"package:sqlite3/src/ffi/libsqlite3.g.dart":["absolute","libsqlite3.arm.android.so"]},"android_arm64":{"package:pdfium_dart/libpdfium":["absolute","libpdfium.so"],"package:sqlite3/src/ffi/libsqlite3.g.dart":["absolute","libsqlite3.arm64.android.so"]},"android_x64":{"package:pdfium_dart/libpdfium":["absolute","libpdfium.so"],"package:sqlite3/src/ffi/libsqlite3.g.dart":["absolute","libsqlite3.x64.android.so"]}}}%

AbiFilters are not used in my project.

[ynnob]

i just updated from 2.2.24 to 2.4.1 and got the same error on android:

Flutter 3.44.0

Call Stack:

Error._throw (c:\Users\[USER]\fvm\versions\3.44.0\bin\cache\pkg\sky_engine\lib\_internal\vm\lib\errors_patch.dart:27)
Error.throwWithStackTrace (c:\Users\[USER]\fvm\versions\3.44.0\bin\cache\pkg\sky_engine\lib\core\errors.dart:120)
_rootHandleError.<anonymous closure> (c:\Users\[USER]\fvm\versions\3.44.0\bin\cache\pkg\sky_engine\lib\async\zone_root.dart:22)
_microtaskLoop (c:\Users\[USER]\fvm\versions\3.44.0\bin\cache\pkg\sky_engine\lib\async\schedule_microtask.dart:40)
_startMicrotaskLoop (c:\Users\[USER]\fvm\versions\3.44.0\bin\cache\pkg\sky_engine\lib\async\schedule_microtask.dart:49)
_runPendingImmediateCallback (c:\Users\[USER]\fvm\versions\3.44.0\bin\cache\pkg\sky_engine\lib\_internal\vm\lib\isolate_patch.dart:127)
_RawReceivePort._handleMessage (c:\Users\[USER]\fvm\versions\3.44.0\bin\cache\pkg\sky_engine\lib\_internal\vm\lib\isolate_patch.dart:193)

Exception:

_Exception (Exception: Failed to load PDFium module: Exception: Native assets file not found.)

I solved this by:

1. delete build directory
2. flutter clean
3. flutter pub get

[espresso3389]

According to @ynnob, it is just a flutter clean issue. @test0terter0n do you still have the issue? If the issue is resolved, please close the issue.

[test0terter0n]

@espresso3389 issue also happens in our ci where we don't have a cached build directory.