Directory.Build.targets

<?xml version="1.0" encoding="utf-8"?>
<Project InitialTargets="ApplyPackageVersions" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

  <ItemGroup>
    <!-- Stores the package versions specified in individual projects -->
    <ProjectSpecifiedPackageVersion Include="@(PackageVersion)" />
  </ItemGroup>

  <Import Project="$(PackageVersionsFile)" />

  <ItemGroup>

    <!-- Clear package versions that are duplicated from a project and the central package versions file -->
    <PackageVersion Remove="@(ProjectSpecifiedPackageVersion)" />
    
    <!-- Add back the project specified package versions -->
    <PackageVersion Include="@(ProjectSpecifiedPackageVersion)" />

    <!-- Stores the original package references used later to determine if there are any problems -->
    <OriginalPackageReference Include="@(PackageReference)" />

    <!-- Store all PackageVersion items that do not have a PackageReference -->
    <_PackagesNotReferenced Include="@(PackageVersion)" Exclude="@(PackageReference)" />

    <!-- Clear the PackageReference list -->
    <PackageReference Remove="@(OriginalPackageReference)" />

    <!-- Add back the PackageReference its from the list that contains versions, excluding the items not referenced -->
    <PackageReference Include="@(PackageVersion)" Exclude="@(_PackagesNotReferenced)" />

    <!-- Clear the temporary list of items not referenced -->
    <_PackagesNotReferenced Remove="@(_PackagesNotReferenced)" />

  </ItemGroup>

  <Target Name="ApplyPackageVersions"
    Condition=" '@(PackageReference)' != '' ">

    <!-- Determine all of the original PackageReference items that did not have a PackageVersion -->
    <ItemGroup>
      <MissingPackageReference Include="@(OriginalPackageReference)" Exclude="@(PackageVersion)" />
    </ItemGroup>
    
    <!--
      Generate an error if any PackageReference has a version specified and its not an implicit item
     -->
    <Error
      Text="The package reference '%(OriginalPackageReference.Identity)' should not specify a version.  Please specify the version in '$(PackageVersionsFile)'."
      Condition=" '%(OriginalPackageReference.IsImplicitlyDefined)' != 'true' And '%(OriginalPackageReference.Version)' != '' "
      File="$(MSBuildProjectFullPath) "/>

    <!--
      Generate an error if any explicit PackageReference did not have matching PackageVersion
     -->
    <Error
      Text="The package reference '%(MissingPackageReference.Identity)' must have a version defined in '$(PackageVersionsFile)'."
      Condition=" '@(MissingPackageReference)' != '' And '%(MissingPackageReference.IsImplicitlyDefined)' != 'true' "
      File="$(MSBuildProjectFullPath)" />

    <!--
      Generate an error if any implicit PackageReference did not have matching PackageVersion
     -->
    <Error
      Text="The implicit package reference '%(MissingPackageReference.Identity)' must have a version defined in '$(PackageVersionsFile)'."
      Condition=" '@(MissingPackageReference)' != '' And '%(MissingPackageReference.IsImplicitlyDefined)' == 'true' "
      File="$(MSBuildProjectFullPath)" />
  </Target>

</Project>