[Regression] .NET 10 RC2 prunes `System.ValueTuple` package when multi-targeting `net462` and `net10.0`

[philipp-naused]

Describe the bug

When multi-targeting net462 and net10.0 using .NET 10.0 RC2, the compiler fails to find type System.ValueTuple when building net462.

To Reproduce

Build this with .NET 10 SDK RC2

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFrameworks>net462;net10.0</TargetFrameworks>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="System.ValueTuple" Version="4.6.1" />
  </ItemGroup>
</Project>

public class Class1
{
    public (int, int) GetTuple() => (1, 2);
}

result:

Restore complete (0.5s)
    info NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy
  test1 net10.0 succeeded (0.1s) → bin\Debug\net10.0\test1.dll
  test1 net462 failed with 1 error(s) (0.1s)
    D:\ws\BugRepos\NET10RC2ValueTuple\test1\Class1.cs(3,12): error CS8179: Predefined type 'System.ValueTuple`2' is not defined or imported

Build failed with 1 error(s) in 1.0s

This is a regression compared to RC1.
This doesn't occur with a target framework newer than 462 or older than .NET 10.
This error also doesn't occur when adding a project reference to an empty library targeting netstandard2.0.

Further technical details

details of dotnet --info

.NET SDK:
 Version:           10.0.100-rc.2.25502.107
 Commit:            89c8f6a112
 Workload version:  10.0.100-manifests.4d32cd9e
 MSBuild version:   18.0.0-preview-25502-107+89c8f6a11

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.26100
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\10.0.100-rc.2.25502.107\

.NET workloads installed:
There are no installed workloads to display.
Configured to use workload sets when installing new manifests.
No workload sets are installed. Run "dotnet workload restore" to install a workload set.

Host:
  Version:      10.0.0-rc.2.25502.107
  Architecture: x64
  Commit:       89c8f6a112

.NET SDKs installed:
  8.0.415 [C:\Program Files\dotnet\sdk]
  9.0.306 [C:\Program Files\dotnet\sdk]
  10.0.100-rc.1.25451.107 [C:\Program Files\dotnet\sdk]
  10.0.100-rc.2.25502.107 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 8.0.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 9.0.10 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 10.0.0-rc.2.25502.107 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 8.0.21 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 9.0.10 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 10.0.0-rc.2.25502.107 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 8.0.21 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 9.0.10 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 10.0.0-rc.2.25502.107 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

[Kielek]

I can confirm, we have same/similar issue in OpenTelemetry repositories, Example: open-telemetry/opentelemetry-dotnet#6602

[philipp-naused]

I have gotten several strange errors related to ValueTuple in .NET Framework when using RC2.
e.g.,

C:\Program Files\dotnet\sdk\10.0.100-rc.2.25502.107\Microsoft.Common.CurrentVersion.targets(2437,5): error MSB3277:
      Found conflicts between different versions of "System.ValueTuple" that could not be resolved.
      There was a conflict between "System.ValueTuple, Version=4.0.2.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" and "System.ValueTuple, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51".
          "System.ValueTuple, Version=4.0.2.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" was chosen because it was primary and "System.ValueTuple, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" was not.
          References which depend on "System.ValueTuple, Version=4.0.2.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" [C:\Program Files\dotnet\sdk\10.0.100-rc.2.25502.107\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\System.ValueTuple.dll].
              C:\Program Files\dotnet\sdk\10.0.100-rc.2.25502.107\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\System.ValueTuple.dll
                Project file item includes which caused reference "C:\Program Files\dotnet\sdk\10.0.100-rc.2.25502.107\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\System.ValueTuple.dll".
                  System.ValueTuple
          References which depend on or have been unified to "System.ValueTuple, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51" [].
              D:\packages\nuget\system.text.json\10.0.0-rc.2.25502.107\lib\net462\System.Text.Json.dll
                Project file item includes which caused reference "D:\packages\nuget\system.text.json\10.0.0-rc.2.25502.107\lib\net462\System.Text.Json.dll".
                  D:\packages\nuget\system.text.json\10.0.0-rc.2.25502.107\lib\net462\System.Text.Json.dll
                  D:\packages\nuget\microsoft.extensions.dependencymodel\6.0.2\lib\net461\Microsoft.Extensions.DependencyModel.dll
                  D:\packages\nuget\microsoft.testing.extensions.codecoverage\18.1.0\lib\netstandard2.0\Microsoft.CodeCoverage.Core.dll
                  D:\packages\nuget\microsoft.testing.extensions.codecoverage\18.1.0\lib\netstandard2.0\Microsoft.CodeCoverage.Instrumentation.dll
                  D:\packages\nuget\microsoft.testing.extensions.codecoverage\18.1.0\lib\netstandard2.0\Microsoft.CodeCoverage.Interprocess.dll
                  D:\packages\nuget\microsoft.testing.extensions.codecoverage\18.1.0\lib\netstandard2.0\Microsoft.Testing.Extensions.CodeCoverage.dll
                  D:\packages\nuget\tunit.core\0.71.0\lib\netstandard2.0\TUnit.Core.dll
                  D:\packages\nuget\tunit.engine\0.71.0\lib\netstandard2.0\TUnit.Engine.dll
              C:\Program Files\dotnet\sdk\10.0.100-rc.2.25502.107\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\netstandard.dll
                Project file item includes which caused reference "C:\Program Files\dotnet\sdk\10.0.100-rc.2.25502.107\Microsoft\Microsoft.NET.Build.Extensions\net461\lib\netstandard.dll".
                  netstandard

And a faulty binding redirect for valuetuple in net48.

But I don't yet have minimal repro steps for these.

[SimonCropp]

i raised a duplicate #51267
will close.

but here is my minimal repro https://github.com/SimonCropp/ValueTupleNet10rc2Repro

[bgrainger]

MySqlConnector is another project affected by this regression: https://github.com/mysql-net/MySqlConnector/blob/135beb56b1c51e27cf6e1360f763d5ed73dc2cbf/src/MySqlConnector/MySqlConnector.csproj#L4.

[PhilippNaused]

I think I found the reason and a workaround!

The package reference to System.ValueTuple is accidentally being pruned. But net462 needs this reference (unless it is indirectly referencing netstandard2.0)

Add this property to disable the pruning:

<RestoreEnablePackagePruning>false</RestoreEnablePackagePruning>

I think these are the PRs that introduced the issue to RC2: #49943 #50348
But they don't seem to be the root cause.

[PhilippNaused]

Pruning isn't supposed to be enabled for .NET Framework. But it doesn't seem to have been prevented.
See: #50816, #50689, #49917