Make incremental build in VS copy output files

Fixes #2306

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

@@ -74,6 +74,11 @@ Copyright (c) .NET Foundation. All rights reserved.
       $(PrepareForRunDependsOn)
     </PrepareForRunDependsOn>
 
+    <GetCopyToOutputDirectoryItemsDependsOn>
+      _RazorGetCopyToOutputDirectoryItems;
+      $(GetCopyToOutputDirectoryItems)
+    </GetCopyToOutputDirectoryItemsDependsOn>
+
   </PropertyGroup>
 
   <!-- 
@@ -266,6 +271,9 @@ Copyright (c) .NET Foundation. All rights reserved.
   <!--
     Gathers input source files for code generation. This is a separate target so that we can avoid
     lots of work when there are no inputs for code generation.
+
+    NOTE: This target is called as part of an incremental build scenario in VS. Do not perform any work
+    outside of calculating RazorGenerate items in this target.
   -->
   <Target Name="ResolveRazorGenerateInputs">
     <!--
@@ -384,7 +392,7 @@ Copyright (c) .NET Foundation. All rights reserved.
   -->
   <Target 
     Name="_RazorGetCopyToOutputDirectoryItems"
-    BeforeTargets="GetCopyToOutputDirectoryItems"
+    DependsOnTargets="ResolveRazorGenerateInputs"
     Condition="'$(ResolvedRazorCompileToolset)'=='RazorSdk' and '$(RazorCompileOnBuild)'=='true'">
 
     <!-- 

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

@@ -100,6 +100,30 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             throw new BuildOutputMissingException(result, match);
         }
 
+        public static void BuildOutputDoesNotContainLine(MSBuildResult result, string match)
+        {
+            if (result == null)
+            {
+                throw new ArgumentNullException(nameof(result));
+            }
+
+            if (match == null)
+            {
+                throw new ArgumentNullException(nameof(match));
+            }
+
+            // We don't really need to search line by line, I'm doing this so that it's possible/easy to debug.
+            var lines = result.Output.Split(new char[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
+            for (var i = 0; i < lines.Length; i++)
+            {
+                var line = lines[i].Trim();
+                if (line == match)
+                {
+                    throw new BuildOutputContainsLineException(result, match);
+                }
+            }
+        }
+
         public static void FileContains(MSBuildResult result, string filePath, string match)
         {
             if (result == null)
@@ -432,6 +456,19 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             protected override string Heading => $"Build did not contain the line: '{Match}'.";
         }
 
+        private class BuildOutputContainsLineException : MSBuildXunitException
+        {
+            public BuildOutputContainsLineException(MSBuildResult result, string match)
+                : base(result)
+            {
+                Match = match;
+            }
+
+            public string Match { get; }
+
+            protected override string Heading => $"Build output contains the line: '{Match}'.";
+        }
+
         private class FileContentFoundException : MSBuildXunitException
         {
             public FileContentFoundException(MSBuildResult result, string filePath, string content, string match)

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

@@ -136,5 +136,42 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
                 Assert.FileDoesNotExist(result, IntermediateOutputPath, "Razor", "Views", "Home", "Index.cshtml.g.cs");
             }
         }
+
+        [Fact]
+        [InitializeTestProject("AppWithP2PReference", additionalProjects: "ClassLibrary")]
+        public async Task IncrementalBuild_WithP2P_WorksWhenBuildProjectReferencesIsDisabled()
+        {
+            // Simulates building the same way VS does by setting BuildProjectReferences=false.
+            // With this flag, the only target called is GetCopyToOutputDirectoryItems on the referenced project.
+            // We need to ensure that we continue providing Razor binaries and symbols as files to be copied over.
+            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, "ClassLibrary.Views.pdb");
+
+            result = await DotnetMSBuild(target: "Clean", "/p:BuildProjectReferences=false", suppressRestore: true);
+            Assert.BuildPassed(result);
+
+            Assert.FileDoesNotExist(result, OutputPath, "AppWithP2PReference.dll");
+            Assert.FileDoesNotExist(result, OutputPath, "AppWithP2PReference.Views.dll");
+            Assert.FileDoesNotExist(result, OutputPath, "ClassLibrary.dll");
+            Assert.FileDoesNotExist(result, OutputPath, "ClassLibrary.Views.dll");
+            Assert.FileDoesNotExist(result, OutputPath, "ClassLibrary.Views.pdb");
+
+            // dotnet msbuild /p:BuildProjectReferences=false
+            result = await DotnetMSBuild(target: default, "/p:BuildProjectReferences=false", suppressRestore: true);
+
+            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, "ClassLibrary.Views.pdb");
+        }
     }
 }

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

@@ -45,5 +45,31 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.BuildPassed(result);
             Assert.BuildOutputContainsLine(result, "UseRazorBuildServer: false");
         }
+
+        [Fact]
+        [InitializeTestProject("ClassLibrary")]
+        public async Task GetCopyToOutputDirectoryItems_WhenNoFileIsPresent_ReturnsEmptySequence()
+        {
+            var result = await DotnetMSBuild(target: default);
+
+            Assert.BuildPassed(result);
+
+            Assert.FileExists(result, OutputPath, "ClassLibrary.dll");
+            Assert.FileExists(result, OutputPath, "ClassLibrary.Views.dll");
+
+            result = await DotnetMSBuild(target: "GetCopyToOutputDirectoryItems", "/t:_IntrospectGetCopyToOutputDirectoryItems /p:BuildProjectReferences=false", suppressRestore: true);
+            Assert.BuildPassed(result);
+            Assert.BuildOutputContainsLine(result, "AllItemsFullPathWithTargetPath: ClassLibrary.Views.dll");
+            Assert.BuildOutputContainsLine(result, "AllItemsFullPathWithTargetPath: ClassLibrary.Views.pdb");
+
+            // Remove all views from the class library
+            Directory.Delete(Path.Combine(Project.DirectoryPath, "Views"), recursive: true);
+
+            // dotnet msbuild /p:BuildProjectReferences=false
+            result = await DotnetMSBuild(target: "GetCopyToOutputDirectoryItems", "/t:_IntrospectGetCopyToOutputDirectoryItems /p:BuildProjectReferences=false", suppressRestore: true);
+
+            Assert.BuildOutputDoesNotContainLine(result, "AllItemsFullPathWithTargetPath: ClassLibrary.Views.dll");
+            Assert.BuildOutputDoesNotContainLine(result, "AllItemsFullPathWithTargetPath: ClassLibrary.Views.pdb");
+        }
     }
 }

test/testapps/RazorTest.Introspection.targets

@@ -18,4 +18,8 @@
   <Target Name="_IntrospectUseRazorBuildServer">
     <Message Text="UseRazorBuildServer: $(UseRazorBuildServer)" Importance="High" />
   </Target>
+
+  <Target Name="_IntrospectGetCopyToOutputDirectoryItems">
+    <Message Text="AllItemsFullPathWithTargetPath: %(AllItemsFullPathWithTargetPath.TargetPath)" Importance="High" />
+  </Target>
 </Project>