Do not generate MVC attributes unless necessary

Fixes https://github.com/aspnet/AspNetCore/issues/8161
\n\nCommit migrated from a976b80c7c

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

@@ -28,30 +28,44 @@ Copyright (c) .NET Foundation. All rights reserved.
   </PropertyGroup>
 
   <!--
-      Configure MVC specific configuration if the application uses a configuration that supports MVC.
+      Resolve MVC specific configuration depending on the presence of MVC specific Razor files.
   -->
-  <PropertyGroup Condition="'$(AddRazorSupportForMvc)' == 'true'">
-    <!--
-      MVC uses a ProvideApplicationPartFactoryAttribute on the generated assembly to load compiled views from assembly. Set this to false, to prevent generating this attribute.
-    -->
-    <GenerateProvideApplicationPartFactoryAttribute Condition="'$(GenerateProvideApplicationPartFactoryAttribute)'==''">true</GenerateProvideApplicationPartFactoryAttribute>
+  <Target Name="_ResolveMvcSpecificRazorConfiguration"
+    DependsOnTargets="ResolveRazorGenerateInputs"
+    Condition="'$(Language)' == 'C#' AND '$(AddRazorSupportForMvc)' == 'true'">
 
-    <!--
-      Determines if the Sdk is allowed to add additional attributes to the project assembly.
-      For instance, MVC will generally want to add attributes to support view discovery and runtime compilation.
-    -->
-    <GenerateRazorAssemblyInfo Condition="'$(GenerateRazorAssemblyInfo)'==''">true</GenerateRazorAssemblyInfo>
+    <Message Text="@(RazorGenerateWithTargetPath)" Importance="High" />
 
-    <!--
-      MVC will generally want to add support for runtime compilation, but only for applications.
-    -->
-    <GenerateRazorHostingAssemblyInfo Condition="'$(GenerateRazorHostingAssemblyInfo)'=='' AND '$(OutputType)'=='exe'">$(GenerateRazorAssemblyInfo)</GenerateRazorHostingAssemblyInfo>
+   <PropertyGroup Condition="'@(RazorGenerate->Count())' != '0'">
+      <!--
+        MVC uses a ProvideApplicationPartFactoryAttribute on the generated assembly to load compiled views from assembly. Set this to false, to prevent generating this attribute.
+      -->
+      <GenerateProvideApplicationPartFactoryAttribute Condition="'$(GenerateProvideApplicationPartFactoryAttribute)'==''">true</GenerateProvideApplicationPartFactoryAttribute>
 
-    <!--
-      The type name of the ApplicationPartFactory applied to the generated Razor file.
-    -->
-    <ProvideApplicationPartFactoryAttributeTypeName Condition="'$(ProvideApplicationPartFactoryAttributeTypeName)' == ''">Microsoft.AspNetCore.Mvc.ApplicationParts.CompiledRazorAssemblyApplicationPartFactory, Microsoft.AspNetCore.Mvc.Razor</ProvideApplicationPartFactoryAttributeTypeName>
-  </PropertyGroup>
+      <!--
+        Determines if the Sdk is allowed to add additional attributes to the project assembly.
+        For instance, MVC will generally want to add attributes to support view discovery and runtime compilation.
+      -->
+      <GenerateRazorAssemblyInfo Condition="'$(GenerateRazorAssemblyInfo)'==''">true</GenerateRazorAssemblyInfo>
+
+      <!--
+        The type name of the ApplicationPartFactory applied to the generated Razor file.
+      -->
+      <ProvideApplicationPartFactoryAttributeTypeName Condition="'$(ProvideApplicationPartFactoryAttributeTypeName)' == ''">Microsoft.AspNetCore.Mvc.ApplicationParts.CompiledRazorAssemblyApplicationPartFactory, Microsoft.AspNetCore.Mvc.Razor</ProvideApplicationPartFactoryAttributeTypeName>
+    </PropertyGroup>
+
+    <ItemGroup Condition="'$(GenerateProvideApplicationPartFactoryAttribute)' == 'true' AND '$(ProvideApplicationPartFactoryAttributeTypeName)'!=''">
+      <RazorTargetAssemblyAttribute Include="Microsoft.AspNetCore.Mvc.ApplicationParts.ProvideApplicationPartFactoryAttribute">
+        <_Parameter1>$(ProvideApplicationPartFactoryAttributeTypeName)</_Parameter1>
+      </RazorTargetAssemblyAttribute>
+    </ItemGroup>
+
+    <ItemGroup Condition="'$(GenerateRazorAssemblyInfo)'=='true' AND '$(ResolvedRazorCompileToolset)'=='RazorSdk' AND ('$(RazorCompileOnBuild)' == 'true' OR '$(RazorCompileOnPublish)' == 'true')">
+      <_RazorAssemblyAttribute Include="Microsoft.AspNetCore.Mvc.ApplicationParts.RelatedAssemblyAttribute">
+        <_Parameter1>$(RazorTargetName)</_Parameter1>
+      </_RazorAssemblyAttribute>
+    </ItemGroup>
+  </Target>
 
   <!--
     Determine the default Razor configuration
@@ -80,16 +94,4 @@ Copyright (c) .NET Foundation. All rights reserved.
     </RazorExtension>
   </ItemGroup>
 
-  <ItemGroup Condition="'$(GenerateRazorAssemblyInfo)'=='true' AND '$(ResolvedRazorCompileToolset)'=='RazorSdk' AND ('$(RazorCompileOnBuild)' == 'true' OR '$(RazorCompileOnPublish)' == 'true')">
-    <_RazorAssemblyAttribute Include="Microsoft.AspNetCore.Mvc.ApplicationParts.RelatedAssemblyAttribute">
-      <_Parameter1>$(RazorTargetName)</_Parameter1>
-    </_RazorAssemblyAttribute>
-  </ItemGroup>
-
-  <ItemGroup Condition="'$(GenerateProvideApplicationPartFactoryAttribute)' == 'true' AND '$(ProvideApplicationPartFactoryAttributeTypeName)'!=''">
-    <RazorTargetAssemblyAttribute Include="Microsoft.AspNetCore.Mvc.ApplicationParts.ProvideApplicationPartFactoryAttribute">
-      <_Parameter1>$(ProvideApplicationPartFactoryAttributeTypeName)</_Parameter1>
-    </RazorTargetAssemblyAttribute>
-  </ItemGroup>
-
 </Project>

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

@@ -32,6 +32,11 @@ Copyright (c) .NET Foundation. All rights reserved.
       _CreateRazorTargetAssemblyInfoInputsCacheFile;
       CoreGenerateRazorTargetAssemblyInfo
     </GenerateRazorTargetAssemblyInfoDependsOn>
+
+    <GenerateRazorTargetAssemblyInfoDependsOn Condition="'$(_Targeting30OrNewerRazorLangVersion)' == 'true'">
+      _ResolveMvcSpecificRazorConfiguration;
+      $(GenerateRazorTargetAssemblyInfoDependsOn)
+    </GenerateRazorTargetAssemblyInfoDependsOn>
   </PropertyGroup>
 
   <Target
@@ -156,9 +161,9 @@ Copyright (c) .NET Foundation. All rights reserved.
     DependsOnTargets="_CreateRazorAssemblyInfoInputsCacheFile"
     Inputs="$(_RazorAssemblyInfoInputsCacheFile)"
     Outputs="$(_RazorAssemblyInfo)"
-    Condition="'@(_RazorAssemblyAttribute)' != ''">
+    Condition="'$(GenerateRazorAssemblyInfo)' == 'true' AND '@(_RazorAssemblyAttribute)' != ''">
 
-    <ItemGroup Condition="'$(GenerateRazorAssemblyInfo)'=='true'">
+    <ItemGroup>
       <Compile Remove="$(_RazorAssemblyInfo)" />
       <Compile Include="$(_RazorAssemblyInfo)" />
     </ItemGroup>
@@ -173,11 +178,18 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <PropertyGroup>
     <!-- Generate attributes in the main assembly if we're targeting a C# project and using the Razor Sdk. -->
-    <CoreCompileDependsOn Condition="'$(ResolvedRazorCompileToolset)'=='RazorSdk' and '$(Language)' == 'C#' and '$(GenerateRazorAssemblyInfo)' == 'true'">
-      $(CoreCompileDependsOn);_GenerateRazorAssemblyInfo
+    <CoreCompileDependsOn Condition="'$(ResolvedRazorCompileToolset)'=='RazorSdk' and '$(Language)' == 'C#'">
+      $(CoreCompileDependsOn);
+      _GenerateRazorAssemblyInfo
     </CoreCompileDependsOn>
 
-    <_GenerateRazorAssemblyInfoDependsOn>PrepareForBuild;_CoreGenerateRazorAssemblyInfo</_GenerateRazorAssemblyInfoDependsOn>
+    <_GenerateRazorAssemblyInfoDependsOn>RazorGetAssemblyAttributes;PrepareForBuild;_CoreGenerateRazorAssemblyInfo</_GenerateRazorAssemblyInfoDependsOn>
+
+    <!-- In 3.0 or later, we need to invoke a target to determine MVC specific configuration. -->
+    <_GenerateRazorAssemblyInfoDependsOn Condition="'$(_Targeting30OrNewerRazorLangVersion)' == 'true'">
+      _ResolveMvcSpecificRazorConfiguration;
+      $(_GenerateRazorAssemblyInfoDependsOn);
+    </_GenerateRazorAssemblyInfoDependsOn>
   </PropertyGroup>
 
   <Target Name="_GenerateRazorAssemblyInfo" DependsOnTargets="$(_GenerateRazorAssemblyInfoDependsOn)" />

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

@@ -407,9 +407,6 @@ Copyright (c) .NET Foundation. All rights reserved.
     The SDK expects configurations that use runtime compilation to set $(GenerateRazorHostingAssemblyInfo) to true,
     it will be unset by default.
   -->
-  <PropertyGroup>
-    <_GenerateRazorAssemblyInfoDependsOn>RazorGetAssemblyAttributes;$(_GenerateRazorAssemblyInfoDependsOn)</_GenerateRazorAssemblyInfoDependsOn>
-  </PropertyGroup>
 
   <Target
     Name="RazorGetAssemblyAttributes"

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

@@ -379,9 +379,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
             Assert.BuildPassed(result);
 
-            Assert.FileExists(result, razorAssemblyInfo);
-            Assert.FileDoesNotContain(result, razorAssemblyInfo, "RelatedAssemblyAttribute");
-
+            Assert.FileDoesNotExist(result, razorAssemblyInfo);
             Assert.FileDoesNotExist(result, IntermediateOutputPath, "SimpleMvc.RazorTargetAssemblyInfo.cs");
         }
 
@@ -454,8 +452,8 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.BuildPassed(result);
 
             Assert.FileExists(result, razorAssemblyInfo);
-            Assert.FileDoesNotContain(result, razorAssemblyInfo, "Microsoft.AspNetCore.Razor.Hosting.RazorLanguageVersionAttribute(\"2.1\")");
-            Assert.FileDoesNotContain(result, razorAssemblyInfo, "Microsoft.AspNetCore.Razor.Hosting.RazorConfigurationNameAttribute(\"MVC-2-1\")");
+            Assert.FileDoesNotContain(result, razorAssemblyInfo, "Microsoft.AspNetCore.Razor.Hosting.RazorLanguageVersionAttribute");
+            Assert.FileDoesNotContain(result, razorAssemblyInfo, "Microsoft.AspNetCore.Razor.Hosting.RazorConfigurationNameAttribute");
         }
 
         [Fact]

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

@@ -26,7 +26,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
         [Fact]
         [InitializeTestProject("ComponentApp")]
-        public async Task Build_DoesNotProduceMvcArtifacts_IfAddRazorSupportForMvcIsFalse()
+        public async Task Build_DoesNotProduceMvcArtifacts_IfProjectDoesNotContainRazorGenerateItems()
         {
             var result = await DotnetMSBuild("Build");
 

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

@@ -14,9 +14,9 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
         {
         }
 
-        [Fact]
+         [Fact]
         [InitializeTestProject("SimpleMvc")]
-        public async Task Build_WithMvc_AddsConfigurationMetadata()
+        public async Task Build_DoesNotAddHostingMetadata_ByDefault()
         {
             var razorAssemblyInfo = Path.Combine(IntermediateOutputPath, "SimpleMvc.RazorAssemblyInfo.cs");
             var result = await DotnetMSBuild("Build");
@@ -26,6 +26,37 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.Views.dll");
             Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.Views.pdb");
 
+            Assert.FileExists(result, razorAssemblyInfo);
+            Assert.FileContainsLine(
+                result,
+                razorAssemblyInfo,
+                "[assembly: Microsoft.AspNetCore.Mvc.ApplicationParts.RelatedAssemblyAttribute(\"SimpleMvc.Views\")]");
+            Assert.FileDoesNotContainLine(
+                result,
+                razorAssemblyInfo,
+                "[assembly: Microsoft.AspNetCore.Razor.Hosting.RazorLanguageVersionAttribute(\"3.0\")]");
+            Assert.FileDoesNotContainLine(
+                result,
+                razorAssemblyInfo,
+                "[assembly: Microsoft.AspNetCore.Razor.Hosting.RazorConfigurationNameAttribute(\"MVC-3.0\")]");
+            Assert.FileDoesNotContainLine(
+                result,
+                razorAssemblyInfo,
+                "[assembly: Microsoft.AspNetCore.Razor.Hosting.RazorExtensionAssemblyNameAttribute(\"MVC-3.0\", \"Microsoft.AspNetCore.Mvc.Razor.Extensions\")]");
+        }
+
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task Build_WithGenerateRazorHostingAssemblyInfo_AddsConfigurationMetadata()
+        {
+            var razorAssemblyInfo = Path.Combine(IntermediateOutputPath, "SimpleMvc.RazorAssemblyInfo.cs");
+            var result = await DotnetMSBuild("Build", "/p:GenerateRazorHostingAssemblyInfo=true");
+
+            Assert.BuildPassed(result);
+
+            Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.Views.dll");
+            Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.Views.pdb");
+
             Assert.FileExists(result, razorAssemblyInfo);
             Assert.FileContainsLine(
                 result,

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

@@ -29,7 +29,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.FileDoesNotExist(result, OutputPath, "SimpleMvc.Views.pdb");
 
             // This target should be part of the design time build.
-            Assert.Contains("RazorGetAssemblyAttributes", result.Output);
+            Assert.Contains("_GenerateRazorAssemblyInfo", result.Output);
 
             // We don't want to see the expensive Razor targets in the performance summary, since they shouldn't run
             // during a design time build.

src/Razor/test/testassets/ComponentApp/ComponentApp.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <RazorSdkDirectoryRoot>$(RazorSdkArtifactsDirectory)$(Configuration)\sdk-output\</RazorSdkDirectoryRoot>
-    <_RazorComponentInclude>**\*.cshtml</_RazorComponentInclude>
+    <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
   </PropertyGroup>
 
   <PropertyGroup>