Custom TFM compat with net8.0 TFM

[Rosentti]

I define a custom TFM like so:

<!-- This is responsible for allowing us to define our custom native1.0 TFM -->

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup Condition="'$(TargetFramework)' == 'native1.0'">
        <TargetFrameworkIdentifier>Native</TargetFrameworkIdentifier>
        <TargetFrameworkVersion>v1.0</TargetFrameworkVersion>
        <TargetFrameworkProfile>Profile1</TargetFrameworkProfile>
    </PropertyGroup>
</Project>

And the import in my .proj (stripped for convenience)

<Import Project="Sdk.props" Sdk="Microsoft.Build.NoTargets" Version="3.7.0" />

<!-- The hook import -->
<Import Project="CustomTargetFrameworkParsingTarget.props"/>

<PropertyGroup>
        <TargetFramework>native1.0</TargetFramework>
</PropertyGroup>

<Import Project="Sdk.targets" Sdk="Microsoft.Build.NoTargets" Version="3.7.0" />

This works great, but I can't depend on the outputs of the .proj through a .csproj as it complains about incompatibilities:
Project TestNative is not compatible with net8.0 (.NETCoreApp,Version=v8.0). Project TestNative supports: native10 (native,Version=v1.0)

How could I make my native1.0 TFM compatible with net8.0?
I could also just use net8.0, but I'd like this to not be dependent on a .NET TFM.

[KalleOlaviNiemitalo]

I'm not sure about custom TFM, but other TFM conflicts can be forced with metadata like this:

<ItemGroup>
  <ProjectReference Include="../Tool/Tool.csproj">
    <SkipGetTargetFrameworkProperties>true</SkipGetTargetFrameworkProperties>
    <SetTargetFramework>TargetFramework=net462</SetTargetFramework>
  </ProjectReference>
</ItemGroup>

Perhaps it'd work with <SetTargetFramework>TargetFramework=native1.0</SetTargetFramework>, then.
According to dotnet/sdk#2280 (comment), SkipGetTargetFrameworkProperties isn't even required.

NuGet might still have trouble with this, though. NuGet/Home#5154

[Rosentti]

Thanks. That got me in the right direction.
This works but is pretty suboptimal:

• Ideally I'd like to set any ReferenceOutputAssembly to false from TestProject.proj (eventually a NuGet package), so the projectreference would be cleaner. I only export "content" from TestProject.proj.
• SetTargetFramework seems to be necessary unfortunately

<ProjectReference ReferenceOutputAssembly="False" SetTargetFramework="TargetFramework=native1.0" Include="..\TestProject\TestProject.proj" />

[Rosentti]

Making TestProject a .nativeproj made it possible to get rid of SetTargetFramework, but ReferenceOutputAssembly is still required.

[Rosentti]

I'd also be fine with the TestProject just having no targetframework (since there's only Content), but MSBuild really doesn't seem to like that.

[Rosentti]

Solved with

<TargetFramework>native</TargetFramework>

and making TestProject a .nativeproj.
ReferenceOutputAssembly="False" seems to always be necessary.