Limit PreserveCompilationReferences to netcoreapp (<2.x)and net4x projects

\n\nCommit migrated from b9c695c2d5

src/Razor/Microsoft.NET.Sdk.Razor/src/build/netstandard2.0/Sdk.Razor.CurrentVersion.props

@@ -42,14 +42,6 @@ Copyright (c) .NET Foundation. All rights reserved.
     -->
     <CopyRazorGenerateFilesToPublishDirectory Condition="'$(CopyRazorGenerateFilesToPublishDirectory)'==''">false</CopyRazorGenerateFilesToPublishDirectory>
 
-    <!--
-      Set to true to copy reference assembly items to the publish directory.
-
-      Typically reference assemblies are not needed for a published application if Razor compilation occurs at build-time
-      or publish-time. By default, the Razor SDK will suppress the copying of reference assemblies to the publish directory.
-    -->
-    <CopyRefAssembliesToPublishDirectory Condition="'$(CopyRefAssembliesToPublishDirectory)'==''">false</CopyRefAssembliesToPublishDirectory>
-
     <!--
     Determines the toolset to use to compile Razor (.cshtml) files. Defaults to 'Implicit' to let the Razor Sdk determine the toolset to use.
     Valid values include 'Implicit', 'RazorSdk', and 'PrecompilationTool'.

src/Razor/Microsoft.NET.Sdk.Razor/src/build/netstandard2.0/Sdk.Razor.CurrentVersion.targets

@@ -217,6 +217,12 @@ Copyright (c) .NET Foundation. All rights reserved.
     <CopyRefAssembliesToPublishDirectory Condition="'$(MvcRazorExcludeRefAssembliesFromPublish)'=='true'">false</CopyRefAssembliesToPublishDirectory>
     <CopyRefAssembliesToPublishDirectory Condition="'$(MvcRazorExcludeRefAssembliesFromPublish)'=='false'">true</CopyRefAssembliesToPublishDirectory>
 
+    <!-- Use PreserveCompilationReferences to determine the behavior of CopyRefAssembliesToPublishDirectory if not explicitly specified by the project. -->
+    <CopyRefAssembliesToPublishDirectory Condition="'$(CopyRefAssembliesToPublishDirectory)'==''">$(PreserveCompilationReferences)</CopyRefAssembliesToPublishDirectory>
+
+    <!-- For 2.x projects desktop and .NET Core projects, if they're opting in to runtime compilation (indicated by PreserveCompilationContext=true), set PreserveCompilationReferences = true -->
+    <PreserveCompilationReferences Condition="'$(PreserveCompilationContext)' == 'true' AND (('$(TargetFrameworkIdentifier)' == '.NETFramework') OR ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' AND '$(_TargetFrameworkVersionWithoutV)' &lt; '3.0'))">true</PreserveCompilationReferences>
+
     <!--
       We can't set the actual default value here due to evaluation order (depends on $(OutDir)).
 
@@ -279,9 +285,11 @@ Copyright (c) .NET Foundation. All rights reserved.
   <!-- Back-compat for PrecompilationTool -->
   <PropertyGroup>
     <!--
-      Always enable PreserveCompilationReferences for non 3.0 projects. This preserves parity with the 2.x SDK's behavior.
+      For 2.x desktop targeting projects using MvcPrecompilation, ref assemblies are required to compile the PrecompiledViews.dll,
+      but are removed by the tool once done. Set PreserveCompilationReferences = true, ignoring any value configured in the project,
+      if the project is using the precompilation tool.
     -->
-    <PreserveCompilationReferences Condition="'$(_TargetingNETCoreApp30OrLater)' != 'true'">true</PreserveCompilationReferences>
+    <PreserveCompilationReferences Condition="'$(ResolvedRazorCompileToolset)'=='PrecompilationTool'">true</PreserveCompilationReferences>
   </PropertyGroup>
 
   <!--
@@ -801,10 +809,10 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Target
     Name="_RazorRemoveRefAssembliesFromPublish"
     BeforeTargets="PrepareForPublish"
-    Condition="'$(ResolvedRazorCompileToolset)'=='RazorSdk' and '$(RazorCompileOnPublish)'=='true' AND '$(CopyRefAssembliesToPublishDirectory)'!=''">
+    Condition="'$(ResolvedRazorCompileToolset)'=='RazorSdk' and '$(RazorCompileOnPublish)'=='true' AND '$(CopyRefAssembliesToPublishDirectory)' != ''">
     <!--
       Setting PreserveCompilationReferences affects both Build and Publish, but we want CopyRefAssembliesToPublishDirectory to only affect publishing.
-      If CopyRefAssembliesToPublishDirectory is disabled, clear PreserveCompilationReferences to stop publishing ref assemblies.
+      Use the value of CopyRefAssembliesToPublishDirectory to determine PreserveCompilationReferences during publish.
     -->
     <PropertyGroup>
       <PreserveCompilationReferences>$(CopyRefAssembliesToPublishDirectory)</PreserveCompilationReferences>

src/Razor/Microsoft.NET.Sdk.Razor/test/IntegrationTests/BuildWithComponentsIntegrationTest.cs

@@ -74,6 +74,36 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.FileDoesNotExist(result, OutputPath, "ComponentLibrary.Views.pdb");
         }
 
+        [Fact]
+        [InitializeTestProject("ComponentLibrary")]
+        public async Task Build_DoesNotProduceRefsDirectory()
+        {
+            TargetFramework = "netstandard2.0";
+
+            // Build
+            var result = await DotnetMSBuild("Build");
+
+            Assert.BuildPassed(result);
+
+            Assert.FileExists(result, OutputPath, "ComponentLibrary.dll");
+           Assert.FileCountEquals(result, 0, Path.Combine(OutputPath, "refs"), "*.dll");
+        }
+
+        [Fact]
+        [InitializeTestProject("ComponentLibrary")]
+        public async Task Publish_DoesNotProduceRefsDirectory()
+        {
+            TargetFramework = "netstandard2.0";
+
+            // Build
+            var result = await DotnetMSBuild("Publish");
+
+            Assert.BuildPassed(result);
+
+            Assert.FileExists(result, PublishOutputPath, "ComponentLibrary.dll");
+            Assert.FileCountEquals(result, 0, Path.Combine(PublishOutputPath, "refs"), "*.dll");
+        }
+
         private async Task Build_ComponentsWorks(MSBuildProcessKind msBuildProcessKind)
         {
             var result = await DotnetMSBuild("Build", msBuildProcessKind: msBuildProcessKind);

src/Razor/Microsoft.NET.Sdk.Razor/test/IntegrationTests/PublishIntegrationTest.cs

@@ -144,8 +144,6 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.FileCountEquals(result, 0, Path.Combine(PublishOutputPath, "refs"), "*.dll");
         }
 
-
-
         [Fact]
         [InitializeTestProject("SimpleMvc")]
         public async Task Publish_NoopsWith_RazorCompileOnPublishFalse()