Make sure RazorSdk works when BuildingInVisualStudio \ BuildProjectReferences is disabled

Fixes #2247

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

@@ -69,6 +69,11 @@ Copyright (c) .NET Foundation. All rights reserved.
       _RazorAddDebugSymbolsProjectOutputGroupOutput
     </DebugSymbolsProjectOutputGroupDependsOn>
 
+    <PrepareForRunDependsOn>
+      _RazorPrepareForRun;
+      $(PrepareForRunDependsOn)
+    </PrepareForRunDependsOn>
+
   </PropertyGroup>
 
   <!-- 
@@ -361,6 +366,15 @@ Copyright (c) .NET Foundation. All rights reserved.
     
   </Target>
 
+  <!--
+    Set up RazorCompile to run before PrepareForRun. This should ensure that the Razor dll and pdbs are available to be copied
+    as part of GetCopyToOutputDirectoryItems which is invoked during PrepareForRun.
+  -->
+  <Target
+    Name="_RazorPrepareForRun"
+    DependsOnTargets="RazorCompile"
+    Condition="'$(ResolvedRazorCompileToolset)'=='RazorSdk' and '$(RazorCompileOnBuild)'=='true'" />
+
   <!--
     Called as part of GetCopyToOutputDirectoryItems - this target populates the list of items that get
     copied to the output directory when building as a project reference.
@@ -368,7 +382,6 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Target 
     Name="_RazorGetCopyToOutputDirectoryItems"
     BeforeTargets="GetCopyToOutputDirectoryItems"
-    DependsOnTargets="RazorCompile"
     Condition="'$(ResolvedRazorCompileToolset)'=='RazorSdk' and '$(RazorCompileOnBuild)'=='true'">
 
     <!-- 

test/Microsoft.AspNetCore.Razor.Design.Test/IntegrationTests/BuildIntegrationTest.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.IO;
 using System.Linq;
 using System.Reflection;
@@ -472,6 +473,41 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.FileDoesNotExist(result, OutputPath, "SimpleMvcFSharp.Views.pdb");
         }
 
+        [Fact]
+        [InitializeTestProject("AppWithP2PReference", additionalProjects: new[] { "ClassLibrary", "ClassLibrary2" })]
+        public async Task Build_WithP2P_WorksWhenBuildProjectReferencesIsDisabled()
+        {
+            // Simulates building the same way VS does by setting BuildProjectReferences=false.
+            // With this flag, P2P references aren't resolved during GetCopyToOutputDirectoryItems. This test ensures that
+            // no Razor work is done in such a scenario and the build succeeds.
+            var additionalProjectContent = @"
+<ItemGroup>
+  <ProjectReference Include=""..\ClassLibrary2\ClassLibrary2.csproj"" />
+</ItemGroup>
+";
+            AddProjectFileContent(additionalProjectContent);
+
+            var result = await DotnetMSBuild(target: default);
+
+            Assert.BuildPassed(result);
+
+            Assert.FileExists(result, OutputPath, "AppWithP2PReference.dll");
+            Assert.FileExists(result, OutputPath, "AppWithP2PReference.Views.dll");
+            Assert.FileExists(result, OutputPath, "ClassLibrary.dll");
+            Assert.FileExists(result, OutputPath, "ClassLibrary.Views.dll");
+            Assert.FileExists(result, OutputPath, "ClassLibrary2.dll");
+            Assert.FileExists(result, OutputPath, "ClassLibrary2.Views.dll");
+
+            // Force a rebuild of ClassLibrary2 by changing a file
+            var class2Path = Path.Combine(Project.SolutionPath, "ClassLibrary2", "Class2.cs");
+            File.AppendAllText(class2Path, Environment.NewLine + "// Some changes");
+
+            // dotnet msbuild /p:BuildProjectReferences=false
+            result = await DotnetMSBuild(target: default, "/p:BuildProjectReferences=false", suppressRestore: true);
+
+            Assert.BuildPassed(result);
+        }
+
         private static DependencyContext ReadDependencyContext(string depsFilePath)
         {
             var reader = new DependencyContextJsonReader();

test/Microsoft.AspNetCore.Razor.Design.Test/IntegrationTests/InitializeTestProjectAttribute.cs

@@ -37,7 +37,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             }
 
             MSBuildIntegrationTestBase.Project = ProjectDirectory.Create(_originalProjectName, _testProjectName, _baseDirectory, _additionalProjects, _language);
-            MSBuildIntegrationTestBase.TargetFramework = _originalProjectName == "ClassLibrary" ? "netstandard2.0" : "netcoreapp2.0";
+            MSBuildIntegrationTestBase.TargetFramework = _originalProjectName.StartsWith("ClassLibrary") ? "netstandard2.0" : "netcoreapp2.0";
         }
 
         public override void After(MethodInfo methodUnderTest)

test/Microsoft.AspNetCore.Razor.Design.Test/IntegrationTests/MSBuildIntegrationTestBase.cs

@@ -79,7 +79,12 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
                 buildArgumentList.Add($"/p:_RazorSuppressCurrentUserOnlyPipeOptions=true");
             }
 
-            buildArgumentList.Add($"/t:{target} /p:Configuration={Configuration} {args}");
+            if (!string.IsNullOrEmpty(target))
+            {
+                buildArgumentList.Add($"/t:{target}");
+            }
+
+            buildArgumentList.Add($"/p:Configuration={Configuration} {args}");
             var buildArguments = string.Join(" ", buildArgumentList);
 
             return MSBuildProcessManager.RunProcessAsync(

test/testapps/ClassLibrary2/Class2.cs

@@ -0,0 +1,13 @@
+using System;
+using ClassLibrary;
+
+namespace ClassLibrary2
+{
+    public class Class2
+    {
+        public void Method()
+        {
+            Console.WriteLine(typeof(Class1));
+        }
+    }
+}

test/testapps/ClassLibrary2/ClassLibrary2.csproj

@@ -0,0 +1,27 @@
+<Project Sdk="Microsoft.NET.Sdk.Razor">
+  
+  <PropertyGroup>
+    <_RazorMSBuildRoot>$(SolutionRoot)src\Microsoft.AspNetCore.Razor.Design\bin\$(Configuration)\netstandard2.0\</_RazorMSBuildRoot>
+  </PropertyGroup>
+
+  <Import Project="$(SolutionRoot)src\Microsoft.AspNetCore.Razor.Design\build\netstandard2.0\Microsoft.AspNetCore.Razor.Design.props" />
+
+  <PropertyGroup>
+    <!-- Override for the MVC extension -->
+    <_MvcExtensionAssemblyPath>$(SolutionRoot)src\Microsoft.AspNetCore.Mvc.Razor.Extensions\bin\$(Configuration)\netstandard2.0\Microsoft.AspNetCore.Mvc.Razor.Extensions.dll</_MvcExtensionAssemblyPath>
+  </PropertyGroup>
+  <Import Project="$(SolutionRoot)src\Microsoft.AspNetCore.Mvc.Razor.Extensions\build\netstandard2.0\Microsoft.AspNetCore.Mvc.Razor.Extensions.props" />
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+  </PropertyGroup>
+  
+  <ItemGroup>
+    <ProjectReference Include="..\ClassLibrary\ClassLibrary.csproj" />
+  </ItemGroup>
+
+  <!-- Test Placeholder -->
+
+  <Import Project="$(SolutionRoot)src\Microsoft.AspNetCore.Mvc.Razor.Extensions\build\netstandard2.0\Microsoft.AspNetCore.Mvc.Razor.Extensions.targets" />
+
+</Project>

test/testapps/ClassLibrary2/Views/Shared/Index.cshtml

@@ -0,0 +1,2 @@
+@{ var message = "Hello world";}
+@message

test/testapps/ClassLibrary2/Views/_ViewImports.cshtml

@@ -0,0 +1,2 @@
+@using ClassLibrary
+@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers