Override NuGet/Paket package references with local projects

Directory.Build.targets

<?xml version="1.0" encoding="utf-8"?>
<Project>
  <!--
  Override NuGet (or Paket) references with a set of local projects.
  Usage:
  * Add this file at the root above all your projects, so that they all gain the capability to override a package.
  * In a solution where you want to override a package, add a file Directory.Build.props like the following:

<?xml version="1.0" encoding="utf-8"?>
<Project>
  <ItemGroup>
    <PackageOverride Include="PackageA">
      <Projects>$(MSBuildThisFileDirectory)PackageA\PackageA\PackageA.csproj</Projects>
    </PackageOverride>
    <PackageOverride Include="PackageB">
      <Projects>
        $(MSBuildThisFileDirectory)PackageB\PackageB.AssemblyA\PackageB.AssemblyA.csproj;
        $(MSBuildThisFileDirectory)PackageB\PackageB.AssemblyB\PackageB.AssemblyB.csproj
      </Projects>
    </PackageOverride>
    <PackageOverride Include="PackageC">
      <Assemblies>
        $(MSBuildThisFileDirectory)PackageB\PackageB.AssemblyA\bin\Debug\net452\PackageB.AssemblyA.dll;
        $(MSBuildThisFileDirectory)PackageB\PackageB.AssemblyB\bin\Debug\net452\PackageB.AssemblyB.dll
      </Assemblies>
    </PackageOverride>
  </ItemGroup>
</Project>

  With the above:
   * Any project that references the package PackageA will reference the project PackageA instead.
   * Any project that references the package PackageB will reference the projects PackageB.AssemblyA and PackageB.AssemblyB instead.
   * Any project that references the package PackageC will reference the assemblies listed instead.

  If there's a Directory.Build.targets anywhere in your solution, add the following at the top of it so that it keeps looking for this one:

  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.targets', '$(MSBuildThisFileDirectory)../'))" Condition="Exists($([MSBuild]::GetPathOfFileAbove('Directory.Build.targets', '$(MSBuildThisFileDirectory)../')))" />

  Similarly, if there's a Directory.Build.props anywhere in your solution, add the following at the top of it so that it keeps looking for your overrides:

  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.targets', '$(MSBuildThisFileDirectory)../'))" Condition="Exists($([MSBuild]::GetPathOfFileAbove('Directory.Build.targets', '$(MSBuildThisFileDirectory)../')))" />

  CAVEAT: This script correctly overrides transitive dependencies of package dependencies; however it does not override transitive dependencies of project dependencies.
  That is, if project A depends on local project B, which depends on package P, then overriding P will result in A not referencing P's override.
  To fix this, add a package reference from A to P.
  -->
  <ItemGroup>
    <_OldPackageReference Include="@(PackageReference)" />
    <PackageReference Remove="@(PackageOverride)" /><!-- Works in VS -->
  </ItemGroup>
  <Target Name="_OverridePackages" AfterTargets="CollectPackageReferences">
    <ItemGroup>
      <_PackageOverride Include="@(PackageOverride)"
                        Condition="( '@(PackageReference)' == '@(PackageOverride)' or '@(_OldPackageReference)' == '@(PackageOverride)' ) and %(Identity) != '' " />
      <PackageReference Remove="@(_PackageOverride)" /><!-- Works in dotnet build -->
      <ProjectReference Include="%(_PackageOverride.Projects)"
                        Condition=" '$(MSBuildProjectFullPath)' != %(_PackageOverride.Projects) " />
      <Reference Include="@(_PackageOverride->Metadata('Assemblies'))" />
    </ItemGroup>
    <Warning Text="Overriding NuGet package @(_PackageOverride)" Condition="'%(Identity)' != ''" />
    <!-- <Warning Text="Override assemblies: @(_PackageOverride->Metadata('Assemblies'))" /> -->
  </Target>
</Project>