Multi-targeting breaks when PackageId is specified in a dependency

[Mrcubix]

This is manually transferred from dotnet/runtime#108343

I have found out a couple days ago that I cannot make use of multi-targeting if any of the underlying dependencies have a PackageId Property Declared (Along with a version).

For instance, let's say I have 2 projects, which only differ by the target framework & package version :

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

  <PropertyGroup>
    <TargetFramework>net5</TargetFramework> <!-- the other version uses net6.0 -->
    <LangVersion>preview</LangVersion>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <PropertyGroup>
    <PackageId>Some.Dependency</PackageId> <!-- Commenting fix the issue -->
    <Version>0.5.3.3</Version> <!-- the other version uses 0.6.4.0 -->
    <Authors>Gess1t</Authors>
    <Description>Some Dependency</Description>
    <PackageOutputPath>../nupkg</PackageOutputPath>
    <PackageLicenseExpression>LGPL-3.0-or-later</PackageLicenseExpression>
  </PropertyGroup>

</Project>

Now let's say I have a library that support multi-targeting like such :

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

  <PropertyGroup>
    <TargetFrameworks>net5.0;net6.0</TargetFrameworks>
    <LangVersion>preview</LangVersion>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup Condition=" '$(TargetFramework)' == 'net5.0' ">
    <ProjectReference Include="../Some.Dependency/Some.Dependency.csproj" Version="0.5.3.3" />
  </ItemGroup>

  <ItemGroup Condition=" '$(TargetFramework)' == 'net6.0' ">
    <ProjectReference Include="../Some.Dependency-0.6.x/Some.Dependency-0.6.x.csproj" Version="0.6.4.0" />
  </ItemGroup>

</Project>

If I now try to build an app using this Library in an app targeting net5.0 then I get this error on compilation :

error NU1201: Project Some.Dependency is not compatible with net5.0 (.NETCoreApp,Version=v5.0). Project 
Some.Dependency supports: net6.0 (.NETCoreApp,Version=v6.0)

if i look inside inside project.assets.json in the obj folder, then i can see this :

"targets": {
    "net5.0": {
      "Some.Dependency/0.6.4": {
        "type": "project",
        "framework": "Unsupported,Version=v0.0",
        "compile": {
          "bin/placeholder/Some.Dependency.dll": {}
        },
        "runtime": {
          "bin/placeholder/Some.Dependency.dll": {}
        }
      }
    },
    "net6.0": {
      "Some.Dependency/0.6.4": {
        "type": "project",
        "framework": ".NETCoreApp,Version=v6.0",
        "compile": {
          "bin/placeholder/Some.Dependency.dll": {}
        },
        "runtime": {
          "bin/placeholder/Some.Dependency.dll": {}
        }
      }
    }
  },

For some reasons, Something in the restore process cause something to set the dependency in both target to the latest version of Some.Dependency, instead of the one specified in the condition.

Here is the repo used : https://github.com/Mrcubix/Multi-Targeting-Issue

Any ideas on how I could fix such an issue?

The current workaround I have right now is to create a separate folder for the .NET 6 target and include the source from the other Lib.

Edit: It does not seem like I'm able to remove, override, or modify a PackageId using Properties, AdditionalProperties.

A potentially overkill workaround

I could potentially build the projects in questions, package them, and use a repo specific local nuget feed to instead reference those packages, as PackageReference does not suffer the same issue.
However this seems like a lot of extra setup just to workaround an issue like this, when creating a separate folder and including the sources there gives the same result.

[Mrcubix]

turns out just after giving the update, i found out how to remove the PackageId before nuget restores the project using this target in Directory.Build.* :

<Target Name="RemovePackageId" BeforeTargets="_GenerateRestoreProjectPathWalk" Condition="'$(AssemblyName)' == 'Some.Dependency-0.6.x'">
    
  <PropertyGroup>
    <PackageId></PackageId>
  </PropertyGroup>

  <Message Importance="High" Text="Removed PackageId in Assembly $(AssemblyName)." />
</Target>

This is targeting a specific Assembly, but i could probably figure out a way to check if the assembly is within a defined list.