Move reference assembly logic into root msbuild files (#79268)

* Move reference assembly logic into root msbuild files

That allows other components like the linker that don't reside under src/libraries to build reference assemblies without duplicating the infrastructure.

Directory.Build.props

@@ -41,6 +41,13 @@
     <Platform Condition="'$(Platform)' == '' and '$(InferPlatformFromTargetArchitecture)' == 'true'">$(TargetArchitecture)</Platform>
   </PropertyGroup>
   
+  <PropertyGroup>
+    <!-- Set OutDirName (Arcade specific property that must be set before the Arcade SDK is imported) to change the BaseOutputPath and
+         BaseIntermediateOutputPath properties to include the ref subfolder. -->
+    <IsReferenceAssemblyProject Condition="$([System.IO.Path]::GetFileName('$(MSBuildProjectDirectory)')) == 'ref'">true</IsReferenceAssemblyProject>
+    <OutDirName Condition="'$(IsReferenceAssemblyProject)' == 'true'">$(MSBuildProjectName)$([System.IO.Path]::DirectorySeparatorChar)ref</OutDirName>
+  </PropertyGroup>
+
   <!-- Import the Arcade SDK -->
   <Import Project="Sdk.props" Sdk="Microsoft.DotNet.Arcade.Sdk" />
 
@@ -319,6 +326,31 @@
     <ProduceReferenceAssembly>false</ProduceReferenceAssembly>
   </PropertyGroup>
   
+  <PropertyGroup Condition="'$(IsReferenceAssemblyProject)' == 'true'">
+    <!-- Reference assemblies are special and don't initialize fields or have empty finalizers, etc. -->
+    <RunAnalyzers>false</RunAnalyzers>
+    <!-- disable warnings about unused fields -->
+    <NoWarn>$(NoWarn);CS0169;CS0649;CS8618</NoWarn>
+    <!-- disable CS8597 because we throw null on reference assemblies. -->
+    <NoWarn>$(NoWarn);CS8597</NoWarn>
+    <!-- We base calls from constructors with null literals. -->
+    <NoWarn>$(NoWarn);CS8625</NoWarn>
+    <!-- We dont need to add null annotation within the ref for explicit interface methods. -->
+    <NoWarn>$(NoWarn);CS8617</NoWarn>
+    <!-- No symbols are produced for ref assemblies, but some parts of the SDK still expect pdbs, so we explicitly tell it there are none. -->
+    <!-- Must be set after importing Arcade to override its defaults. -->
+    <DebugType>none</DebugType>
+  </PropertyGroup>
+
+  <!-- All reference assemblies should have a ReferenceAssemblyAttribute and the 0x70 flag which prevents them from loading. -->
+  <ItemGroup Condition="'$(IsReferenceAssemblyProject)' == 'true'">
+    <AssemblyAttribute Include="System.Runtime.CompilerServices.ReferenceAssemblyAttribute" />
+    <AssemblyAttribute Include="System.Reflection.AssemblyFlags">
+      <_Parameter1>(System.Reflection.AssemblyNameFlags)0x70</_Parameter1>
+      <_Parameter1_IsLiteral>true</_Parameter1_IsLiteral>
+    </AssemblyAttribute>
+  </ItemGroup>
+
   <PropertyGroup>
     <CustomBeforeNoTargets>$(RepositoryEngineeringDir)NoTargetsSdk.BeforeTargets.targets</CustomBeforeNoTargets>
     <CustomAfterNoTargets>$(RepositoryEngineeringDir)NoTargetsSdk.AfterTargets.targets</CustomAfterNoTargets>

Directory.Build.targets

@@ -76,6 +76,37 @@
     <Description>$(PackageDescription)</Description>
   </PropertyGroup>
   
+  <ItemDefinitionGroup>
+    <TargetPathWithTargetPlatformMoniker>
+      <IsReferenceAssemblyProject>$(IsReferenceAssemblyProject)</IsReferenceAssemblyProject>
+    </TargetPathWithTargetPlatformMoniker>
+  </ItemDefinitionGroup>
+
+  <Target Name="ValidateReferenceAssemblyProjectReferencesAndTargetFramework"
+          AfterTargets="ResolveReferences"
+          Condition="'$(IsReferenceAssemblyProject)' == 'true' and
+                     '$(SkipValidateReferenceAssemblyProjectReferences)' != 'true'">
+    <Error Text="Reference assemblies must only reference other reference assemblies and '%(ReferencePath.ProjectReferenceOriginalItemSpec)' is not a reference assembly project and does not set 'ProduceReferenceAssembly'."
+           Condition="'%(ReferencePath.ReferenceSourceTarget)' == 'ProjectReference' and '%(ReferencePath.IsReferenceAssemblyProject)' != 'true' and '%(ReferencePath.ReferenceAssembly)' == ''" />
+    <Error Text="Reference assemblies must be TargetPlatform agnostic. $(MSBuildProjectName) incorrectly targets $(TargetFramework), platform: $(TargetPlatformIdentifier)."
+           Condition="'$(TargetPlatformIdentifier)' != ''" />
+  </Target>
+
+  <!-- For experimental ref assemblies (which typically have the same name as a regular ref
+       assembly), bump their minor file version by 100 to make it distinguishable from the regular
+       ref assembly. -->
+  <Target Name="UpdateExperimentalRefAssemblyFileVersion"
+          AfterTargets="_InitializeAssemblyVersion"
+	        Condition="'$(IsReferenceAssemblyProject)' == 'true' and '$(IsExperimentalRefAssembly)' == 'true'">
+    <PropertyGroup>
+      <_FileVersionMaj>$(FileVersion.Split('.')[0])</_FileVersionMaj>
+      <_FileVersionMin>$(FileVersion.Split('.')[1])</_FileVersionMin>
+      <_FileVersionBld>$(FileVersion.Split('.')[2])</_FileVersionBld>
+      <_FileVersionRev>$(FileVersion.Split('.')[3])</_FileVersionRev>
+      <FileVersion>$(_FileVersionMaj).$([MSBuild]::Add($(_FileVersionMin), 100)).$(_FileVersionBld).$(_FileVersionRev)</FileVersion>
+    </PropertyGroup>
+  </Target>
+
   <!--
     Arcade SDK versioning is defined by static properties in a targets file: work around this by
     moving properties based on versioning into a target.

eng/referenceAssemblies.props

@@ -1,29 +0,0 @@
-<Project>
-
-  <PropertyGroup>
-    <!-- Reference assemblies are special and don't initialize fields or have empty finalizers, etc. -->
-    <RunAnalyzers>false</RunAnalyzers>
-
-    <!-- disable warnings about unused fields -->
-    <NoWarn>$(NoWarn);CS0169;CS0649;CS8618</NoWarn>
-
-    <!-- disable CS8597 because we throw null on reference assemblies. -->
-    <NoWarn>$(NoWarn);CS8597</NoWarn>
-
-    <!-- We base calls from constructors with null literals. -->
-    <NoWarn>$(NoWarn);CS8625</NoWarn>
-
-    <!-- We dont need to add null annotation within the ref for explicit interface methods. -->
-    <NoWarn>$(NoWarn);CS8617</NoWarn>
-  </PropertyGroup>
-
-  <!-- All reference assemblies should have a ReferenceAssemblyAttribute and the 0x70 flag which prevents them from loading. -->
-  <ItemGroup>
-    <AssemblyAttribute Include="System.Runtime.CompilerServices.ReferenceAssemblyAttribute" />
-    <AssemblyAttribute Include="System.Reflection.AssemblyFlags">
-      <_Parameter1>(System.Reflection.AssemblyNameFlags)0x70</_Parameter1>
-      <_Parameter1_IsLiteral>true</_Parameter1_IsLiteral>
-    </AssemblyAttribute>
-  </ItemGroup>
-
-</Project>

eng/references.targets

@@ -79,22 +79,6 @@
     </ItemGroup>
   </Target>
 
-  <ItemDefinitionGroup>
-    <TargetPathWithTargetPlatformMoniker>
-      <IsReferenceAssemblyProject>$(IsReferenceAssemblyProject)</IsReferenceAssemblyProject>
-    </TargetPathWithTargetPlatformMoniker>
-  </ItemDefinitionGroup>
-
-  <Target Name="ValidateReferenceAssemblyProjectReferencesAndTargetFramework"
-          AfterTargets="ResolveReferences"
-          Condition="'$(IsReferenceAssemblyProject)' == 'true' and
-                     '$(SkipValidateReferenceAssemblyProjectReferences)' != 'true'">
-    <Error Text="Reference assemblies must only reference other reference assemblies and '%(ReferencePath.ProjectReferenceOriginalItemSpec)' is not a reference assembly project and does not set 'ProduceReferenceAssembly'."
-           Condition="'%(ReferencePath.ReferenceSourceTarget)' == 'ProjectReference' and '%(ReferencePath.IsReferenceAssemblyProject)' != 'true' and '%(ReferencePath.ReferenceAssembly)' == ''" />
-    <Error Text="Reference assemblies must be TargetPlatform agnostic. $(MSBuildProjectName) incorrectly targets $(TargetFramework), platform: $(TargetPlatformIdentifier)."
-           Condition="'$(TargetPlatformIdentifier)' != ''" />
-  </Target>
-
   <!-- An opt-in target to trim out private assemblies from the ref assembly ReferencePath. -->
   <Target Name="TrimOutPrivateAssembliesFromReferencePath"
           Condition="'$(CompileUsingReferenceAssemblies)' == 'true' and '$(TrimOutPrivateAssembliesFromReferencePath)' == 'true'"
@@ -114,19 +98,4 @@
       <ReferencePathWithRefAssemblies Include="@(_resolvedCoreLibProjectReference->Metadata('ReferenceAssembly'))" />
     </ItemGroup>
   </Target>
-
-  <!-- For experimental ref assemblies (which typically have the same name as a regular ref
-       assembly), bump their minor file version by 100 to make it distinguishable from the regular
-       ref assembly. -->
-  <Target Name="UpdateExperimentalRefAssemblyFileVersion"
-          AfterTargets="_InitializeAssemblyVersion"
-	        Condition="'$(IsReferenceAssemblyProject)' == 'true' and '$(IsExperimentalRefAssembly)' == 'true'">
-    <PropertyGroup>
-      <_FileVersionMaj>$(FileVersion.Split('.')[0])</_FileVersionMaj>
-      <_FileVersionMin>$(FileVersion.Split('.')[1])</_FileVersionMin>
-      <_FileVersionBld>$(FileVersion.Split('.')[2])</_FileVersionBld>
-      <_FileVersionRev>$(FileVersion.Split('.')[3])</_FileVersionRev>
-      <FileVersion>$(_FileVersionMaj).$([MSBuild]::Add($(_FileVersionMin), 100)).$(_FileVersionBld).$(_FileVersionRev)</FileVersion>
-    </PropertyGroup>
-  </Target>
 </Project>

src/libraries/Directory.Build.props

@@ -2,11 +2,6 @@
   <PropertyGroup>
     <SkipInferTargetOSName>true</SkipInferTargetOSName>
     <DisableArcadeTestFramework>true</DisableArcadeTestFramework>
-
-    <!-- Set OutDirName to change the BaseOutputPath and BaseIntermediateOutputPath properties to include the ref subfolder. -->
-    <_projectDirName>$([System.IO.Path]::GetFileName('$(MSBuildProjectDirectory)'))</_projectDirName>
-    <IsReferenceAssemblyProject Condition="'$(_projectDirName)' == 'ref'">true</IsReferenceAssemblyProject>
-    <OutDirName Condition="'$(IsReferenceAssemblyProject)' == 'true'">$(MSBuildProjectName)$([System.IO.Path]::DirectorySeparatorChar)ref</OutDirName>
   </PropertyGroup>
 
   <Import Project="..\..\Directory.Build.props" />
@@ -32,7 +27,7 @@
 
   <PropertyGroup>
     <!-- Treat as a generator project if either the parent or the parent parent directory is named gen. -->
-    <IsGeneratorProject Condition="'$(_projectDirName)' == 'gen' or
+    <IsGeneratorProject Condition="$([System.IO.Path]::GetFileName('$(MSBuildProjectDirectory)')) == 'gen' or
                                    $([System.IO.Path]::GetFileName('$([System.IO.Path]::GetFullPath('$(MSBuildProjectDirectory)\..'))')) == 'gen'">true</IsGeneratorProject>
     <IsSourceProject Condition="'$(IsSourceProject)' == '' and
                                 '$(IsReferenceAssemblyProject)' != 'true' and
@@ -69,7 +64,6 @@
   </ItemGroup>
 
   <Import Project="NetCoreAppLibrary.props" />
-  <Import Project="$(RepositoryEngineeringDir)referenceAssemblies.props" Condition="'$(IsReferenceAssemblyProject)' == 'true'" />
   <Import Project="$(RepositoryEngineeringDir)testing\linker\trimmingTests.props" Condition="'$(IsPublishedAppTestProject)' == 'true'" />
 
   <PropertyGroup>