Integrate Solution SDK into legacy solutions

- This starts small with very specific properties set.

- A little bit improvisation in recognition of
  un-supported projects and eliminating them
  from the Build process.

Directory.Build.rsp

@@ -1,5 +1,4 @@
 -NoLogo
--Restore
 -MaxCPUCount
 -BinaryLogger
 -NodeReuse:False

Directory.Solution.props

@@ -6,9 +6,7 @@
 		<RestoreUseStaticGraphEvaluation>True</RestoreUseStaticGraphEvaluation>
 	</PropertyGroup>
 
-	<PropertyGroup Label="Solution">
-		<ImportByWildcardAfterSolution>False</ImportByWildcardAfterSolution>
-		<ImportByWildcardBeforeSolution>False</ImportByWildcardBeforeSolution>
-	</PropertyGroup>
+	<!-- Integrate with the Solution SDK for Legacy Solution files -->
+	<Import Sdk="MSBuild.Solution.Sdk" Project="Sdk.Legacy.props"/>
 
 </Project>

Directory.Solution.targets

@@ -1,6 +1,6 @@
 <Project>
 
-	<!-- Enable Solution-wide Package Restore through our SDK -->
-	<Import Sdk="MSBuild.NET.Legacy.Sdk" Project="NuGet.Restore.targets"/>
+	<!-- Integrate with the Solution SDK for Legacy Solution files -->
+	<Import Sdk="MSBuild.Solution.Sdk" Project="Sdk.Legacy.targets"/>
 
 </Project>

Sources/MSBuild.Solution.Sdk/Sdk/Sdk.Legacy.props

@@ -0,0 +1,11 @@
+<Project>
+
+	<PropertyGroup Label="Solution">
+		<ImportByWildcardAfterSolution>False</ImportByWildcardAfterSolution>
+		<ImportByWildcardBeforeSolution>False</ImportByWildcardBeforeSolution>
+	</PropertyGroup>
+
+	<!-- Enable Solution-wide Central Package Management through our SDK -->
+	<Import Sdk="NuGet.Build.Sdk" Project="Sdk.Extensions.props"/>
+
+</Project>

Sources/MSBuild.Solution.Sdk/Sdk/Sdk.Legacy.targets

@@ -0,0 +1,16 @@
+<Project>
+
+	<Target Name="RemoveUnSupportedProjectsFromRestore"
+			BeforeTargets="Restore;_LoadRestoreGraphEntryPoints;_GenerateProjectRestoreGraphPerFramework;_GenerateRestoreProjectPathItemsPerFramework">
+		<ItemGroup>
+			<UnSupportedProjectReference Include="@(ProjectReference->WithMetadataValue('Extension', '.nuproj'))" />
+			<ProjectReference Remove="@(UnSupportedProjectReference)" />
+		</ItemGroup>
+		<Message Importance="High" Condition="@(UnSupportedProjectReference->Count()) > 0"
+			Text="Restore is not currently supported for NuGet packaging projects (i.e., MSBuild projects with file extension 'nuproj')."/>
+	</Target>
+
+	<!-- Enable Solution-wide Package Restore through our SDK -->
+	<Import Sdk="NuGet.Build.Sdk" Project="Sdk.Restore.targets" />
+
+</Project>

global.json

@@ -3,6 +3,7 @@
 	{
 		"MSBuild.Core.Sdk": "1.0.0-dev.*",
 		"MSBuild.Common.Sdk": "1.0.0-dev.*",
+		"MSBuild.Solution.Sdk": "1.0.0-dev.*",
 
 		"MSBuild.NET.Sdk": "1.0.0-dev.*",
 		"MSBuild.NET.Legacy.Sdk": "1.0.0-dev.*",