Full solution build fails within Visual Studio

[h3xds1nz]

@ViktorHofer It seems like you've broken this in dotnet/dotnet#2177 with the <TargetFramework /> inside the PBT project:

wpf/src/Microsoft.DotNet.Wpf/src/PresentationBuildTasks/PresentationBuildTasks.csproj

Lines 3 to 4 in 4425f57

	<TargetFrameworks>$(BundledNETCoreAppTargetFramework);$(NetFrameworkToolCurrent)</TargetFrameworks>
	<TargetFramework />

Wouldn't something like a conditional on whether NetFrameworkToolCurrent doesn't have a value do the same job with less unpredictable behaviour since I assume when you're building on unix this one will be unset?

Without removing the empty TargetFramework this fails within Visual Studio with error MSB4057: The target "GetTargetPath" does not exist in the project.

[ViktorHofer]

Defining TargetFramework centrally when there's at least one project that multi-targets (defining TargetFrameworks) is an anti-pattern that we just recently documented in one of our msbuild skills. That causes all kinds of issues like this one.

I'm not sure why this would cause an issue though as TargetFramework is passed in as a global property and so L4 shouldn't have any effect in inner builds. This could be a bug in the .NET project system.

[h3xds1nz]

Right, it's caused by the newly added project reference from Microsoft.NET.Sdk.WindowsDesktop.ArchNeutral in that same PR which skips the props via SkipGetTargetFrameworkProperties=true. When you undefine the TFM via UndefineProperties="TargetFramework" metadata on the ProjectReference then it works just fine.

I keep forgetting the entire WPF solution build is a wreck.