ExcludeAssets="Runtime" should not remove frameworkAssemblies

[ericstj]

NuGet Product Used

dotnet.exe

Product Version

dotnet 9.0.100

Worked before?

Don't know

Impact

It's more difficult to complete my work

Repro Steps & Context

Build a project targeting .NET framework and referencing <PackageReference Include="System.ComponentModel.Annotations" Version="5.0.0" />

For example:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFrameworks>net4.8;net8.0</TargetFrameworks>
    <LangVersion>latest</LangVersion>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="System.ComponentModel.Annotations" Version="5.0.0"  />
  </ItemGroup>
</Project>

Note that System.ComponentModel.Annotations contains Framework References and those are correctly resolve on .NETFramework when referenced normally.
From NuSpec:

    <frameworkAssemblies>
      <frameworkAssembly assemblyName="mscorlib" targetFramework=".NETFramework4.6.1" />
      <frameworkAssembly assemblyName="System.ComponentModel.DataAnnotations" targetFramework=".NETFramework4.5" />
      <frameworkAssembly assemblyName="System.ComponentModel.DataAnnotations" targetFramework=".NETFramework4.6.1" />
    </frameworkAssemblies>

From Assets file:

    ".NETFramework,Version=v4.8": {
      "System.ComponentModel.Annotations/5.0.0": {
        "type": "package",
        "frameworkAssemblies": [
          "System.ComponentModel.DataAnnotations",
          "mscorlib"
        ],
        "compile": {
          "ref/net461/System.ComponentModel.Annotations.dll": {
            "related": ".xml"
          }
        },
        "runtime": {
          "lib/net461/System.ComponentModel.Annotations.dll": {}
        }
      }
    },

Now add ExcludeAssets="Runtime" to the reference:

    <PackageReference Include="System.ComponentModel.Annotations" Version="5.0.0"  ExcludeAssets="Runtime" />

NuGet removes the runtime asset, as expected, but also drops the frameworkAssemblies. The latter is incorrect. Framework Assemblies are not runtime assets, they are just references from the targeting pack. They need to be preserved as part of the compile assets.

    ".NETFramework,Version=v4.8": {
      "System.ComponentModel.Annotations/5.0.0": {
        "type": "package",
        "compile": {
          "ref/net461/System.ComponentModel.Annotations.dll": {
            "related": ".xml"
          }
        },
        "runtime": {
          "lib/net461/_._": {}
        }
      }
    },

Verbose Logs

No response

[nkolev92]

This seems like a bug, but it's also a behavior that's always been a thing: https://github.com/NuGet/NuGet.Client/blame/cee6d943f9a6fa38daf5adba4d4dae9d230e83c6/src/NuGet.Core/NuGet.Commands/RestoreCommand/Utility/LockFileUtils.cs#L1059, so likely the impact is pretty low.