Dependency injection fails for Android

[plavoie-nms]

Description

I have this simplified MediatR IPipelineBehavior in a MAUI project:

public class ActiveConnectionRetryPolicyBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
    where TRequest : notnull, IRequest<TResponse>
    where TResponse : Result, new()
{
    public async Task<TResponse> Handle(TRequest request, RequestHandlerDelegate<TResponse> next, CancellationToken cancellationToken)
    {
        if (cancellationToken.IsCancellationRequested)
        {
            var response = new TResponse();
            response.SetException(new TaskCanceledException());

            return response;
        }

        return await next().ConfigureAwait(false);
    }
}

DI:

builder.Services.AddMediatR(x => x.RegisterServicesFromAssembly(typeof(MyApp).Assembly)
                                  .AddOpenBehavior(typeof(ActiveConnectionRetryPolicyBehavior<,>)));

It works perfectly in Windows, but when running it in Android, I get this error:

System.ArgumentException
  Message=Generic implementation type 'MyApp.ActiveConnectionRetryPolicyBehavior`2' has a DefaultConstructorConstraint ('new()' constraint), but the generic service type 'MediatR.IPipelineBehavior`2' doesn't.

Call stack:

   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.ValidateTrimmingAnnotations(Type serviceType, Type[] serviceTypeGenericArguments, Type implementationType, Type[] implementationTypeGenericArguments)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.Populate()
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory..ctor(ICollection`1 descriptors)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider..ctor(ICollection`1 serviceDescriptors, ServiceProviderOptions options)
   at Microsoft.Extensions.DependencyInjection.ServiceCollectionContainerBuilderExtensions.BuildServiceProvider(IServiceCollection services, ServiceProviderOptions options)
   at Microsoft.Extensions.DependencyInjection.ServiceCollectionContainerBuilderExtensions.BuildServiceProvider(IServiceCollection services)
   at Microsoft.Maui.Hosting.MauiAppBuilder.Build() in D:\a\_work\1\s\src\Core\src\Hosting\MauiAppBuilder.cs:line 149
   at ProjectZ.App.MauiProgram.CreateMauiApp() in C:\Sources\Nmedia\Nms.Blazor\ProjectZ.App\MauiProgram.cs:line 42
   at ProjectZ.App.MainApplication.CreateMauiApp() in C:\Sources\Nmedia\Nms.Blazor\ProjectZ.App\Platforms\Android\MainApplication.cs:line 14
   at Microsoft.Maui.MauiApplication.OnCreate() in D:\a\_work\1\s\src\Core\src\Platform\Android\MauiApplication.cs:line 36
   at Android.App.Application.n_OnCreate(IntPtr jnienv, IntPtr native__this) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net8.0/android-34/mcw/Android.App.Application.cs:line 1087
   at Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PP_V(_JniMarshal_PP_V callback, IntPtr jnienv, IntPtr klazz) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:line 26

Steps to Reproduce

No response

Link to public reproduction project repository

No response

Version with bug

8.0.6

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

Android

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output

No response

[Eilon]

Does this happen in Debug builds also, or just Release?

This could be related to 'trimming' which is used for Android builds to remove unused parts of the code to create smaller app sizes. You could try turning it off in the project settings to see if that is the cause. Info here: https://learn.microsoft.com/dotnet/maui/deployment/visual-studio-properties?view=net-maui-8.0

[plavoie-nms]

I only tried in debug mode.

[meierhoeferjannis]

I got the same problem. Are there any news ?