STDERR: Unknown experiment: native-assets

[cruvie]

cruvie@192 flutter_app % flutter run -d macos --enable-flutter-gpu
Launching lib/main.dart on macOS in debug mode...
Unhandled exception:
Exception: Failed to run flutter_scene_importer:import command in build hook (exit code 254):
STDERR: Unknown experiment: native-assets

STDOUT: 
#0      buildModels (package:flutter_scene_importer/build_hooks.dart:46:7)
#1      main.<anonymous closure> (file:///Users/cruvie/Documents/open-source/flutter_scene/examples/flutter_app/hook/build.dart:6:5)
#2      build (package:native_assets_cli/src/api/build.dart:107:16)
#3      main (file:///Users/cruvie/Documents/open-source/flutter_scene/examples/flutter_app/hook/build.dart:5:3)
#4      _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:312:33)
#5      _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:193:12)

  Building assets for package:example_app failed.
  build.dart returned with exit code: 255.
  To reproduce run:
  /Users/cruvie/Documents/flutter/bin/cache/dart-sdk/bin/dart --packages=/Users/cruvie/Documents/open-source/flutter_scene/examples/flutter_app/.dart_tool/package_config.json /Users/cruvie/Documents/open-source/flutter_scene/examples/flutter_app/.dart_tool/hooks_runner/example_app/7ad245dadc068daf8ba9d7bb51a8ef8e/hook.dill --config=/Users/cruvie/Documents/open-source/flutter_scene/examples/flutter_app/.dart_tool/hooks_runner/example_app/7ad245dadc068daf8ba9d7bb51a8ef8e/input.json
  stderr:
  Unhandled exception:
Exception: Failed to run flutter_scene_importer:import command in build hook (exit code 254):
STDERR: Unknown experiment: native-assets

STDOUT: 
#0      buildModels (package:flutter_scene_importer/build_hooks.dart:46:7)
#1      main.<anonymous closure> (file:///Users/cruvie/Documents/open-source/flutter_scene/examples/flutter_app/hook/build.dart:6:5)
#2      build (package:native_assets_cli/src/api/build.dart:107:16)
#3      main (file:///Users/cruvie/Documents/open-source/flutter_scene/examples/flutter_app/hook/build.dart:5:3)
#4      _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:312:33)
#5      _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:193:12)

  stdout:


Target dart_build failed: Error: Building native assets failed. See the logs for more details.
Failed to package /Users/cruvie/Documents/open-source/flutter_scene/examples/flutter_app.
Command PhaseScriptExecution failed with a nonzero exit code
** BUILD FAILED **

Building macOS application...                                           
Error: Build process failed
cruvie@192 flutter_app % 

cruvie@192 flutter_app % flutter config --list
All Settings:
  enable-web: (Not set)
  enable-linux-desktop: (Not set)
  enable-macos-desktop: (Not set)
  enable-windows-desktop: (Not set)
  enable-android: (Not set)
  enable-ios: (Not set)
  enable-fuchsia: (Not set)
  enable-custom-devices: (Not set)
  cli-animations: (Not set)
  enable-native-assets: true
  enable-dart-data-assets: (Not set)
  enable-swift-package-manager: (Not set)
  omit-legacy-version-file: (Not set)
  enable-windowing: (Not set)
  enable-lldb-debugging: (Not set)

cruvie@192 flutter_app % 

cruvie@192 flutter_app % flutter doctor -v
[✓] Flutter (Channel main, 3.37.0-1.0.pre-101, on macOS 15.6.1 24G90 darwin-arm64, locale zh-Hans-CN) [68.6s]
    • Flutter version 3.37.0-1.0.pre-101 on channel main at /Users/cruvie/Documents/flutter
    • Upstream repository git@github.com:flutter/flutter.git
    • Framework revision adca933962 (18 hours ago), 2025-09-12 19:19:41 -0300
    • Engine revision 3310be0332
    • Dart version 3.10.0 (build 3.10.0-195.0.dev)
    • DevTools version 2.50.0
    • Pub download mirror https://pub.flutter-io.cn
    • Flutter download mirror https://storage.flutter-io.cn
    • Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop, enable-android, enable-ios, cli-animations, enable-native-assets, omit-legacy-version-file, enable-lldb-debugging

[xiaowei-guan]

You can try to modify build_hooks.dart:

guanxw@samsung10022:~/flutter-tizen-3.32.4/flutter_scene/examples/flutter_app$ git diff ../../importer/lib/build_hooks.dart
diff --git a/importer/lib/build_hooks.dart b/importer/lib/build_hooks.dart
index 2ee7660..1b8dbb9 100644
--- a/importer/lib/build_hooks.dart
+++ b/importer/lib/build_hooks.dart
@@ -31,8 +31,8 @@ void buildModels({
     final importerResult = Process.runSync(
       dartExec.toFilePath(),
       [
-        '--enable-experiment=native-assets',
         'run',
+        '--enable-experiment=native-assets',
         'flutter_scene_importer:import',
         '--input',
         inputFilePath,

[cruvie]

@xiaowei-guan works now thanks a lot. leave this open until the maintainer fix it in the repo

[lijialin9]

On the Windows platform, I followed the solution provided in the previous reply and made the modifications and ran the program. However, it still reported an error. Although the modifications worked, there were no more detailed prompts. I attempted to compile using VS 2022 by running flutter_scene-master\examples\flutter_app\build\windows\x64\example_app.sln. The error message was "STDERR: Could not find the pub cache. No LOCALAPPDATA environment variable exists. Consider setting the PUB_CACHE variable manually." I'm not sure if this message from VS is helpful, but even after setting the PUB_CACHE, VS still gave the same error.

[lijialin9]

#82 (comment)
This might be a bug in Flutter related to the Windows platform. When Flutter starts the build hook, it fails to initialize the relevant environment variables, causing Process.runSync to be unable to inherit the environment variable LOCALAPPDATA (including using Platform.environment) from the parent process. Therefore, this environment variable needs to be manually specified.

[M3BIONIX]

Raised a PR with fixes #84