Prune data for netcoreapp2.1 and below contains Microsoft.NETCore.App, but it shouldn't

[nkolev92]

Describe the bug

A clear and concise description of what the bug is.

Create a new project that targets netcoreapp2.2 or below.
Enable pruning, run restore & build. Build will fail because the Microsoft.NETCore.App package is pruned.

To Reproduce

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.2</TargetFramework>
    <RestoreEnablePackagePruning>true</RestoreEnablePackagePruning>
  </PropertyGroup>
</Project>

• dotnet build

Restore will mark Microsoft.NETCore.App as IncludeAssets=none because it's prunable, and the build will f ail with missing basic types:

  E:\Code\Temp\pruningns21\obj\Debug\netcoreapp2.1\.NETCoreApp,Version=v2.1.AssemblyAttributes.cs(4,20): error CS0400: The type or namespace name 'System' could not be found in the global namespace (are you m
issing an assembly reference?) [E:\Code\Temp\pruningns21\pruningns21.csproj]

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.1</TargetFramework>
    <RestoreEnablePackagePruning>true</RestoreEnablePackagePruning>
  </PropertyGroup>

  <Target Name="CleanupPruneRefs" AfterTargets="AddPrunePackageReferences">
    <ItemGroup>
      <PrunePackageReference Remove="Microsoft.NETCore.App" />
    </ItemGroup>
  </Target>
</Project>

seems to make things work, but I don't know to know enough whether the rest of the packages should remain pruned.

Now this package Microsoft.NETCore.App is implicitly reference, so there's an argument on what to do with that, but instead of letting NuGet pick, we should fix the data regardless.
Related issue: NuGet/Home#14441

Exceptions (if any)

Further technical details

• Include the output of dotnet --info
• The IDE (VS / VS Code/ VS4Mac) you're running on, and its version

.NET 10, P7.

[nkolev92]

cc @dsplaisted

[marcpopMSFT]

I believe you're changing the default to not prune for EOL targeting but customers can still enable it, correct? Assigning to dsplaisted in case it's easy to just trim those out.

[nkolev92]

For now, in P7, it's being changed to NET8 and later.

We're working through that in NuGet/Home#14442.

Given that customers will be able to enable pruning for these frameworks themselves, I think we have one of the following options:

• Fix the data, Daniel will probably know best.
• Say it's not worth it, and completely remove pruning data for netcoreapp2.2 and below and say pruning is not supported for those frameworks.