bug: flet build apk opencv-python Encountered an error, Failed to package successfully

[yst-one]

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Describe the bug

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To reproduce

1

Expected behavior

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Operating System

Windows

Operating system details

11

Flet version

0.85.3

Regression

Yes, it used to work in a previous Flet version (please specify the version in additional details)

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Additional details

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[FeodorFitsner]

can you provide a less verbose flet build log please?

[yst-one]

can you provide a less verbose flet build log please?请您提供一份更简洁的 Flet 构建日志吧。

(yolo_flet) PS C:\Users\Administrator\PycharmProjects\yolo_flet\examples\yolo_flet_example> uv run flet debug android --device 29e6fb8f
warning: VIRTUAL_ENV=C:\Users\Administrator\PycharmProjects\yolo_flet\.venv does not match the project environment path .venv and will be ignored; use --active to target the active environment instead
[10:31:01] Packaged Python app ✅
Registered Flutter user extensions ✅
[10:31:26] Launching lib\main.dart on Mi 10 in debug mode...
Running Gradle task 'assembleDebug'...
Gradle build config:
minSdkVersion: 24
targetSdkVersion: 36
versionCode: 1
versionName: 1.0.0
Running Gradle task 'assembleDebug'... 21.4s

       FAILURE: Build failed with an exception.                                                                                                                                            
                                                                                                                                                                                           
       * What went wrong:                                                                                                                                                                  
       Execution failed for task ':app:mergeDebugNativeLibs'.                                                                                                                              
       > A failure occurred while executing com.android.build.gradle.internal.tasks.MergeNativeLibsTask$MergeNativeLibsTaskWorkAction                                                      
          > 2 files found with path 'lib/arm64-v8a/libc++_shared.so' from inputs:                                                                                                          
             -                                                                                                                                                                             
       C:\Users\Administrator\PycharmProjects\yolo_flet\examples\yolo_flet_example\build\flutter\build\ultralytics_yolo\intermediates\library_jni\debug\copyDebugJniLibsProjectOnly\jni\arm
       64-v8a\libc++_shared.so                                                                                                                                                             
             -                                                                                                                                                                             
       C:\Users\Administrator\PycharmProjects\yolo_flet\examples\yolo_flet_example\build\flutter\build\serious_python_android\intermediates\library_jni\debug\copyDebugJniLibsProjectOnly\j
       ni\arm64-v8a\libc++_shared.so                                                                                                                                                       
            If you are using jniLibs and CMake IMPORTED targets, see                                                                                                                       
            https://developer.android.com/r/tools/jniLibs-vs-imported-targets                                                                                                              
                                                                                                                                                                                           
       * Try:                                                                                                                                                                              
       > Run with --stacktrace option to get the stack trace.                                                                                                                              
       > Run with --info or --debug option to get more log output.                                                                                                                         
       > Run with --scan to get full insights.                                                                                                                                             
       > Get more help at https://help.gradle.org.                                                                                                                                         
                                                                                                                                                                                           
       BUILD FAILED in 21s                                                                                                                                                                 
       Error: Gradle task assembleDebug failed with exit code 1                                                                                                                            

[10:31:31] Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 3.41.4, on Microsoft Windows [版本 10.0.26200.8457], locale zh-CN)
[√] Windows Version (Windows 11 or higher, 25H2, 2009)
[√] Android toolchain - develop for Android devices (Android SDK version 36.1.0)
[X] Chrome - develop for the web (Cannot find Chrome executable at .\Google\Chrome\Application\chrome.exe)
! Cannot find Chrome. Try setting CHROME_EXECUTABLE to a Chrome executable.
[X] Visual Studio - develop Windows apps
X Visual Studio not installed; this is necessary to develop Windows apps.
Download at https://visualstudio.microsoft.com/downloads/.
Please install the "Desktop development with C++" workload, including all of its default components
[√] Connected device (3 available)
[√] Network resources

       ! Doctor found issues in 2 categories.                                                                                                                                              

╭─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ Error building Flet app - see the log of failed command above.

[ndonkoHenri]

Thanks for the log — that's a Gradle mergeDebugNativeLibs clash.

       Execution failed for task ':app:mergeDebugNativeLibs'.                                                                                                                              
       > A failure occurred while executing com.android.build.gradle.internal.tasks.MergeNativeLibsTask$MergeNativeLibsTaskWorkAction                                                      
          > 2 files found with path 'lib/arm64-v8a/libc++_shared.so' from inputs:                                                                                                          
             -                                                                                                                                                                             
       C:\Users\Administrator\PycharmProjects\yolo_flet\examples\yolo_flet_example\build\flutter\build\ultralytics_yolo\intermediates\library_jni\debug\copyDebugJniLibsProjectOnly\jni\arm
       64-v8a\libc++_shared.so                                                                                                                                                             
             -                                                                                                                                                                             
       C:\Users\Administrator\PycharmProjects\yolo_flet\examples\yolo_flet_example\build\flutter\build\serious_python_android\intermediates\library_jni\debug\copyDebugJniLibsProjectOnly\j
       ni\arm64-v8a\libc++_shared.so    

Two Flutter plugins are each bundling their own copy of libc++_shared.so:

• serious_python_android — Flet's Python runtime ships libc++_shared.so because the cross-compiled Python wheels in pypi.flet.dev link against it.
• ultralytics_yolo — also ships its own copy.

Neither file is wrong; Gradle just needs an explicit policy when more than one input contributes the same path. libc++_shared.so has been ABI-stable since NDK r17, so picking either copy is safe.

A template-side fix is being prepared so the generated android/app/build.gradle.kts carries the policy by default. You can test it right now with a one-line edit to your already-generated build dir.

Open build/flutter/android/app/build.gradle.kts and apply this diff:

     packaging {
         jniLibs {
             useLegacyPackaging = true
             keepDebugSymbols += listOf(
                 "*/arm64-v8a/libpython*.so",
                 "*/armeabi-v7a/libpython*.so",
                 "*/x86/libpython*.so",
                 "*/x86_64/libpython*.so",
             )
+            pickFirsts += listOf("**/libc++_shared.so")
         }
     }

Then re-run your flet command, and mergeDebugNativeLibs should succeed.

[yst-one]

Thanks for the log — that's a Gradle mergeDebugNativeLibs clash.感谢提供的日志——这是 Gradle mergeDebugNativeLibs 冲突导致的。

Execution failed for task ':app:mergeDebugNativeLibs'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.MergeNativeLibsTask$MergeNativeLibsTaskWorkAction
> 2 files found with path 'lib/arm64-v8a/libc++_shared.so' from inputs:
-
C:\Users\Administrator\PycharmProjects\yolo_flet\examples\yolo_flet_example\build\flutter\build\ultralytics_yolo\intermediates\library_jni\debug\copyDebugJniLibsProjectOnly\jni\arm
64-v8a\libc++_shared.so
-
C:\Users\Administrator\PycharmProjects\yolo_flet\examples\yolo_flet_example\build\flutter\build\serious_python_android\intermediates\library_jni\debug\copyDebugJniLibsProjectOnly\j
ni\arm64-v8a\libc++_shared.so

Two Flutter plugins are each bundling their own copy of libc++_shared.so:两个 Flutter 插件各自打包了 libc++_shared.so 的一个副本：

• serious_python_android — Flet's Python runtime ships libc++_shared.so because the cross-compiled Python wheels in pypi.flet.dev link against it.serious_python_android — Flet 的 Python 运行时包含 libc++_shared.so ，因为 pypi.flet.dev 中的交叉编译 Python wheel 链接到它。
• ultralytics_yolo — also ships its own copy.ultralytics_yolo — 也提供自己的副本。

Neither file is wrong; Gradle just needs an explicit policy when more than one input contributes the same path. libc++_shared.so has been ABI-stable since NDK r17, so picking either copy is safe.两个文件都没有问题；Gradle 只需要在多个输入指向同一路径时明确指定处理策略即可。libc libc++_shared.so 自 NDK r17 起就保持了 ABI 稳定性，因此选择其中任何一个版本都是安全的。

A template-side fix is being prepared so the generated android/app/build.gradle.kts carries the policy by default. You can test it right now with a one-line edit to your already-generated build dir.我们正在准备一个模板端的修复方案，以便生成的 android/app/build.gradle.kts 文件默认应用该策略。您现在只需对已生成的构建目录进行一行编辑即可进行测试。

Open build/flutter/android/app/build.gradle.kts and apply this diff:打开 build/flutter/android/app/build.gradle.kts 文件并应用以下差异：

 packaging {
     jniLibs {
         useLegacyPackaging = true
         keepDebugSymbols += listOf(
             "*/arm64-v8a/libpython*.so",
             "*/armeabi-v7a/libpython*.so",
             "*/x86/libpython*.so",
             "*/x86_64/libpython*.so",
         )

•        pickFirsts += listOf("**/libc++_shared.so")
     }
  

  }
  Then re-run your flet command, and mergeDebugNativeLibs should succeed.然后重新运行 flet 命令， mergeDebugNativeLibs 应该会成功。

Yes, the compilation succeeded after I added this line. Thanks a lot! You've done great work.