Linked files run transform from original file location instead of linked location

[jklawrence]

Given a folder structure like:

Foo/
├─ Foo.csproj
├─ Web.config
Bar/
├─ Bar.csproj
├─ Web.Debug.config

And with Bar.csproj including ../Foo/Web.config as a linked file, Slow Cheetah does not apply transforms from Bar's Web.Debug.config file.

Here's Bar.csproj:

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

  <PropertyGroup>
    <TargetFramework>net472</TargetFramework>
    <OutputType>Library</OutputType>
  </PropertyGroup>

  <ItemGroup>
    <None Include="..\Foo\Web.config">
      <Link>Web.config</Link>
      <TransformOnBuild>true</TransformOnBuild>
    </None>
    <None Update="Web.Debug.config">
      <IsTransformFile>True</IsTransformFile>
      <DependentUpon>Web.config</DependentUpon>
    </None>
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\Bar\Bar.csproj" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.VisualStudio.SlowCheetah" Version="4.0.8">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
  </ItemGroup>

</Project>

When running MSBuild with diagnostic verbosity, I can see that it's looking for the TransformFile in the Foo folder instead of Bar:

Added Item(s): 
    _ScNoneFilesToTransform=
        ..\Foo\Web.config
                CopyToOutputDirectory=PreserveNewest
                DestinationFile=obj\Debug\net472\Web.config
                Link=Web.config
                OriginalItemSpec=..\Foo\Web.config
                SourceFile=c:\SomePath\Foo\Web.config
                Subtype=Designer
                TargetPath=Web.config
                TransformFile=..\Foo\Web.Debug.config
                TransformOnBuild=true
                _BuildAction=None

I've worked around this for now by adding a custom target that runs after ScCollectTransformFiles:

  <Target Name="FixSlowCheetahTransformFile" AfterTargets="ScCollectTransformFiles">
    <ItemGroup>
      <ScFilesToTransform Update="..\Foo\Web.config">
        <TransformFile>Web.$(Configuration).config</TransformFile>
      </ScFilesToTransform>
    </ItemGroup>
  </Target>

Is there a supported way to run transforms using the linked file location?