[NativeAot] System.IO.Hashing versions conflict

[tranb3r]

Android framework version

36.x

Affected platform version

VS 2026

Description

When using System.IO.Hashing 10.0.0 in an app and building it with NativeAot, the build fails with an exception caused by multiple versions of System.IO.Hashing being used.
This is probably caused by System.IO.Hashing version pin to 9.0.4: #10043

Steps to Reproduce

• dotnet new maui -n TestNativeAOT
• cd TestNativeAOT
• dotnet add package System.IO.Hashing => should add 10.0.0 version
• dotnet build -bl -f net10.0-android -c Release -r android-arm64 -p:PublishAot=true

Did you find any workaround?

When using package version 9.0.4 instead of 10.0.0 in the app, there is no exception.

Relevant log output

C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\36.1.2\tools\Xamarin.Android.Common.targets(1498,3): error XAAMP7004:
  System.ArgumentException: An item with the same key has already been added. Key: System.IO.Hashing
     at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value)
     at Xamarin.Android.Tasks.MonoAndroidHelper.GetPerArchAssemblies(IEnumerable`1 input, HashSet`1 supportedTargetArches, Boolean validate, Func`2 shouldSkip)
     at Xamarin.Android.Tasks.MonoAndroidHelper.GetPerArchAssemblies(IEnumerable`1 input, ICollection`1 supportedAbis, Boolean validate, Func`2 shouldSkip)
     at Xamarin.Android.Tasks.AssemblyModifierPipeline.RunTask()
     at Microsoft.Android.Build.Tasks.AndroidTask.Execute()

[jonpryor]

Regarding #10043, this sounds like a possible use case for: https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-10/sdk#use-net-msbuild-tasks-with-net-framework-msbuild

[akoeplinger]

I don't think this is related to #10043, that one was about the build task. This fails when gathering the assemblies for the app build.

[jonathanpeppers]

The problem is $(_AndroidTypeMapImplementation)=managed relied on us actually shipping System.IO.Hashing.dll in the Android runtime pack.

Thinking now on this, I wonder if we should have made it use the NuGet package in customers' builds, and then if they put a newer one in the project it would "just work" as long as there are no breaking changes.

[jonathanpeppers]

/cc @simonrozsival

[jonathanpeppers]

I added a test to just verify this isn't an issue on MonoVM or CoreCLR:

• [tests] Add test for System.IO.Hashing 10.0.0 #10614

Long-term, we are revamping the typemaps for NativeAOT, so we think this problem will go away with the new implementation.

But we can leave this open for now, thanks for filing.