[net6] Building an application can sometimes cause `Xamarin.Android.Tasks.TypeMapGenerator.GenerateRelease` to fail

[jeromelaban]

Android application type

Android for .NET (net6.0-android, etc.)

Affected platform version

17.3.0

Description

Building an app can sometimes cause this:

C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\32.0.451\tools\Xamarin.Android.Common.targets(1438,3): error XAGJS7004: System.ArgumentException: An item with the same key has already been added.
   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
   at Xamarin.Android.Tasks.TypeMapGenerator.GenerateRelease(Boolean skipJniAddNativeMethodRegistrationAttributeScan, List`1 javaTypes, String outputDirectory, ApplicationConfigTaskState appConfState)
   at Xamarin.Android.Tasks.GenerateJavaStubs.WriteTypeMappings(List`1 types, TypeDefinitionCache cache)
   at Xamarin.Android.Tasks.GenerateJavaStubs.Run(DirectoryAssemblyResolver res)
   at Xamarin.Android.Tasks.GenerateJavaStubs.RunTask()
   at Microsoft.Android.Build.Tasks.AndroidTask.Execute() in /Users/runner/work/1/s/xamarin-android/external/xamarin-android-tools/src/Microsoft.Android.Build.BaseTasks/AndroidTask.cs:line 17

Steps to Reproduce

1. Build an app
2. ? (maybe have a build failure of some kind)
3. Rebuild, see the failure above.
4. Clean bin/obj
5. Rebuild, the build will succeed.

Did you find any workaround?

Cleaning bin/obj folders.

Relevant log output

android-build-failure.zip

[grendello]

This is most likely fixed by dotnet/runtime#67660, would you be able to test your application with a NET7 preview build of Xamarin.Android?

[jeromelaban]

I could do that. I was under the impression that net7 builds were not ready to be used, but is there a guide to do this kind of testing?

[grendello]

@jeromelaban https://github.com/xamarin/xamarin-android/blob/main/Documentation/guides/InstallBuildsFromMain.md should help!

[jonathanpeppers]

@jeromelaban if you are hitting this in .NET 6 with the .NET 6 SDK, can you give some more details about the project you got this error? (I think the .binlog is from VS, and doesn't have the .csproj in it) Do you know if a specific NuGet package causes it?

I think you would hit this with Release builds only.

[jonathanpeppers]

I can reproduce this when building a .NET 6 MAUI app with a .NET 7 SDK, it appears to be hitting this line:

https://github.com/xamarin/xamarin-android/blob/863cfc540e97134ad6a8875eae31007ec39889ce/src/Xamarin.Android.Build.Tasks/Utilities/TypeMapGenerator.cs#L395

https://github.com/xamarin/xamarin-android/blob/d6224ca6b1032ffebc8fe2b496f93a511b0674a6/src/Xamarin.Android.Build.Tasks/Utilities/TypeMapGenerator.cs#L385

@grendello can we just change this collection to a List<T>? Then we should probably also backport this change to .NET 6.

[jeromelaban]

@jonathanpeppers I don't recall exactly in which context that could happen, but it seems you've found a way to repro it :) Thanks!