Upload error in the app in release mode.

[yurijdvornyk]

I am trying to upload a file to S3 with a presigned URL.
Everything works fine in debug build, however when I run the app in release mode, I am getting the following error:

2021-05-18 15:51:06.931 16494-17980/? E/UploadWorker: exception encountered
    java.lang.RuntimeException: Missing type parameter.
        at b.b.c.M.a.<init>(:3)
        at com.bluechilli.flutteruploader.t.<init>(Unknown Source:0)
        at com.bluechilli.flutteruploader.UploadWorker.l(Unknown Source:112)
        at com.bluechilli.flutteruploader.UploadWorker.a(Unknown Source:0)
        at com.bluechilli.flutteruploader.k.run(Unknown Source:4)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:923)

2021-05-18 15:51:06.938 16494-16589/? I/WM-WorkerWrapper: Worker result FAILURE for Work [ id=645254f3-b9a7-4812-8f95-6e9a5fc16c6d, tags={ flutter_upload_task, com.bluechilli.flutteruploader.UploadWorker } ]

Then, I am getting 500 response (despite everything is fine, the URL is valid and I have full permissions to write to S3 bucket). What could cause such behavior?

flutter doctor -v:

[✓] Flutter (Channel stable, 2.0.2, on macOS 11.1 20C69 darwin-x64, locale en-GB)
    • Flutter version 2.0.2 at /Users/yurii.dvornyk/Documents/flutter
    • Framework revision 8962f6dc68 (10 weeks ago), 2021-03-11 13:22:20 -0800
    • Engine revision 5d8bf811b3
    • Dart version 2.12.1

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
    • Android SDK at <...>/Library/Android/sdk
    • Platform android-30, build-tools 30.0.2
    • ANDROID_HOME = <...>/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.5, Build version 12E262
    • CocoaPods version 1.10.1

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 4.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)

[✓] VS Code (version 1.56.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.22.0

[✓] Connected device (3 available)
    • Pixel 3a (mobile)       • 93RAY0EM5W                • android-arm64  • Android 11 (API 30)
    • U — iPhone (2) (mobile) • 00008020-001145D40EC2002E • ios            • iOS 14.0.1
    • Chrome (web)            • chrome                    • web-javascript • Google Chrome 90.0.4430.212

[ened]

@yurijdvornyk which plugin version are you using?

[yurijdvornyk]

@ened , I have to use 3.0.0-beta1 to be able to use it in the project with sounding null-safety.

[cristik]

Ran into the same issue, this Stackoverflow post has the fix for it.

Basically, add the following lines to android/app/proguard-rules.pro

-keep class com.google.gson.reflect.TypeToken
-keep class * extends com.google.gson.reflect.TypeToken
-keep public class * implements java.lang.reflect.Type

Seems that when the app is shrunk (which happens when building for Release), some reflection details are stripped away, causing the issue. An alternative would be to use -dontshrink in the proguard-rules.pro file, however I think this is a more extreme approach.