Bootstrap stage 2 build failure in Microsoft.Build.Tasks.Git.LocateRepository task

[mthalman]

/vmr/.dotnet/sdk/8.0.100-preview.4.23219.1/Sdks/Microsoft.Build.Tasks.Git/build/Microsoft.Build.Tasks.Git.targets(26,5): error MSB4018: The "Microsoft.Build.Tasks.Git.LocateRepository" task failed unexpectedly.
System.InvalidCastException: [A]System.Runtime.CompilerServices.StrongBox`1[Microsoft.Build.Tasks.Git.GitRepository] cannot be cast to [B]System.Runtime.CompilerServices.StrongBox`1[Microsoft.Build.Tasks.Git.GitRepository]. Type A originates from 'System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' in the context 'Default' at location '/vmr/.dotnet/shared/Microsoft.NETCore.App/8.0.0-preview.4.23217.4/System.Private.CoreLib.dll'. Type B originates from 'System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' in the context 'Default' at location '/vmr/.dotnet/shared/Microsoft.NETCore.App/8.0.0-preview.4.23217.4/System.Private.CoreLib.dll'.
   at Microsoft.Build.Tasks.Git.RepositoryTask.TryGetCachedRepositoryInstance(String cacheKey, Boolean requireCached, GitRepository& repository)
   at Microsoft.Build.Tasks.Git.RepositoryTask.GetOrCreateRepositoryInstance()
   at Microsoft.Build.Tasks.Git.RepositoryTask.ExecuteImpl()
   at Microsoft.Build.Tasks.Git.RepositoryTask.Execute()
   at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
   at Microsoft.Build.BackEnd.TaskBuilder.ExecuteInstantiatedTask(ITaskExecutionHost taskExecutionHost, TaskLoggingContext taskLoggingContext, TaskHost taskHost, ItemBucket bucket, TaskExecutionMode howToExecuteTask) [/vmr/src/source-build-reference-packages/artifacts/source-build/self/src/src/targetPacks/ILsrc/microsoft.netcore.app.ref/7.0.0/Microsoft.NETCore.App.Ref.7.0.0.csproj]

This occurs in the dependency project build of SBRP when attempting to build Microsoft.NETCore.App.Ref.7.0.0.

Build link (internal only)

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[mthalman]

This seems related to the addition of Microsoft.Build.Tasks.Git.8.0.0-beta.23210.3 to the prebuilts.

[MichaelSimons]

[Triage] The fix for dotnet/sdk#31863 should have come in this morning so this should be fixed.

[MichaelSimons]

This is still not resolved.

[MichaelSimons]

It's possible the packages from prebuilts are causing this. Removing them in dotnet/installer#16176.

[MichaelSimons]

It's possible the packages from prebuilts are causing this. Removing them in dotnet/installer#16176.

Unfortunately it didn't resolve the issue.

[mthalman]

@tmat, @ViktorHofer - Could you help in determining the cause of this failure?

For context, this is failing in the bootstrap build workflow where we source-build the https://github.com/dotnet/dotnet repo once and then use the outputted SDK as the toolset to build the source again. It fails in that second build.

I've attached the build's binlog:
sourcebuild-dependency-projects.zip

What's odd about the exception message is that it's complaining that Type A can't be cast to Type B even though it reports that Type A and B are the same type from the same assembly file. I suspect that it's possible the message is actually wrong here given that it's a generic type and the real casting issue is with the GitRepository type. It doesn't indicate anything about that type's assembly in the error.

Here's the relevant code doing the cast: https://github.com/dotnet/dotnet/blob/e2903bde31921e07bebca58f03f6b1395dd74802/src/sourcelink/src/Microsoft.Build.Tasks.Git/RepositoryTask.cs#L150

It's possible that use of an MSBuild registered task object is a factor here.