Fixup incremental builds with ApplicationPartsDiscovery (dotnet/aspnetcore-tooling#693)

\n\nCommit migrated from df3c4d533a

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

@@ -25,12 +25,13 @@ Copyright (c) .NET Foundation. All rights reserved.
     </CoreCompileDependsOn>
 
     <_MvcApplicationPartAttributeGeneratedFile>$(IntermediateOutputPath)$(TargetName).MvcApplicationPartsAssemblyInfo$(DefaultLanguageSourceExtension)</_MvcApplicationPartAttributeGeneratedFile>
+    <_MvcApplicationPartCacheFile>$(IntermediateOutputPath)$(TargetName).MvcApplicationPartsAssemblyInfo.cache</_MvcApplicationPartCacheFile>
   </PropertyGroup>
 
   <Target
     Name="_DiscoverMvcApplicationParts"
     Inputs="$(ProjectAssetsFile);$(MSBuildAllProjects)"
-    Outputs="$(_MvcApplicationPartAttributeGeneratedFile)"
+    Outputs="$(_MvcApplicationPartCacheFile)"
     DependsOnTargets="ResolveAssemblyReferences">
 
     <ItemGroup>
@@ -73,7 +74,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       In this case, delete the file so that future incremental builds can no longer pick it up.
     -->
     <Delete
-      File="$(_MvcApplicationPartAttributeGeneratedFile)"
+      Files="$(_MvcApplicationPartAttributeGeneratedFile)"
       Condition="'@(_ApplicationPartAssemblyNames->Count())' == '0' AND Exists('$(_MvcApplicationPartAttributeGeneratedFile)')" />
 
     <ItemGroup Condition="Exists('$(_MvcApplicationPartAttributeGeneratedFile)')">
@@ -82,6 +83,8 @@ Copyright (c) .NET Foundation. All rights reserved.
 
       <CompileBefore Remove="$(_MvcApplicationPartAttributeGeneratedFile)" Condition="'$(Language)'=='F#'" />
       <CompileBefore Include="$(_MvcApplicationPartAttributeGeneratedFile)"  Condition="'$(Language)'=='F#'" />
+
+      <FileWrites Include="$(_MvcApplicationPartAttributeGeneratedFile)"/>
     </ItemGroup>
 
     <!--
@@ -89,11 +92,11 @@ Copyright (c) .NET Foundation. All rights reserved.
       This is required to play nicely with incremental builds.
     -->
     <Touch
-      Files="$(_MvcApplicationPartAttributeGeneratedFile)"
+      Files="$(_MvcApplicationPartCacheFile)"
       AlwaysCreate="true" />
 
     <ItemGroup>
-      <FileWrites Include="$(_MvcApplicationPartAttributeGeneratedFile)" />
+      <FileWrites Include="$(_MvcApplicationPartCacheFile)" />
     </ItemGroup>
   </Target>
 </Project>

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

@@ -45,9 +45,10 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
             Assert.BuildPassed(result);
 
-            Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.MvcApplicationPartsAssemblyInfo.cs");
+            Assert.FileDoesNotExist(result, IntermediateOutputPath, "SimpleMvc.MvcApplicationPartsAssemblyInfo.cs");
-            // We should produced an empty file for build incrementalism
+
-            Assert.Empty(File.ReadAllText(Path.Combine(result.Project.DirectoryPath, IntermediateOutputPath, "SimpleMvc.MvcApplicationPartsAssemblyInfo.cs")));
+            // We should produced a cache file for build incrementalism
+            Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.MvcApplicationPartsAssemblyInfo.cache");
         }
 
         [Fact]
@@ -59,18 +60,30 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.BuildPassed(result);
 
             var generatedAttributeFile = Path.Combine(IntermediateOutputPath, "AppWithP2PReference.MvcApplicationPartsAssemblyInfo.cs");
+            var cacheFile = Path.Combine(IntermediateOutputPath, "AppWithP2PReference.MvcApplicationPartsAssemblyInfo.cache");
+            var outputFile = Path.Combine(IntermediateOutputPath, "AppWithP2PReference.dll");
             Assert.FileExists(result, generatedAttributeFile);
             Assert.FileContains(result, generatedAttributeFile, "[assembly: Microsoft.AspNetCore.Mvc.ApplicationParts.ApplicationPartAttribute(\"ClassLibrary\")]");
 
-            var thumbPrint = GetThumbPrint(generatedAttributeFile);
+            var generatedFilethumbPrint = GetThumbPrint(generatedAttributeFile);
+            var cacheFileThumbPrint = GetThumbPrint(cacheFile);
+            var outputFileThumbPrint = GetThumbPrint(outputFile);
 
-            result = await DotnetMSBuild("Build");
+            await AssertIncrementalBuild();
+            await AssertIncrementalBuild();
 
-            Assert.BuildPassed(result);
+            async Task AssertIncrementalBuild()
+            {
+                result = await DotnetMSBuild("Build");
 
-            Assert.FileExists(result, generatedAttributeFile);
+                Assert.BuildPassed(result);
-            Assert.Equal(thumbPrint, GetThumbPrint(generatedAttributeFile));
+
-            Assert.AssemblyHasAttribute(result, Path.Combine(OutputPath, "AppWithP2PReference.dll"), "Microsoft.AspNetCore.Mvc.ApplicationParts.ApplicationPartAttribute");
+                Assert.FileExists(result, generatedAttributeFile);
+                Assert.Equal(generatedFilethumbPrint, GetThumbPrint(generatedAttributeFile));
+                Assert.Equal(cacheFileThumbPrint, GetThumbPrint(cacheFile));
+                Assert.Equal(outputFileThumbPrint, GetThumbPrint(outputFile));
+                Assert.AssemblyHasAttribute(result, Path.Combine(OutputPath, "AppWithP2PReference.dll"), "Microsoft.AspNetCore.Mvc.ApplicationParts.ApplicationPartAttribute");
+            }
         }
 
         // Regression test for https://github.com/aspnet/AspNetCore/issues/11315
@@ -128,17 +141,30 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.BuildPassed(result);
 
             var generatedAttributeFile = Path.Combine(IntermediateOutputPath, "SimpleMvc.MvcApplicationPartsAssemblyInfo.cs");
-            Assert.FileExists(result, generatedAttributeFile);
+            var cacheFile = Path.Combine(IntermediateOutputPath, "SimpleMvc.MvcApplicationPartsAssemblyInfo.cache");
-            Assert.Empty(File.ReadAllText(Path.Combine(result.Project.DirectoryPath, generatedAttributeFile)));
+            var outputFile = Path.Combine(IntermediateOutputPath, "SimpleMvc.dll");
+            Assert.FileDoesNotExist(result, generatedAttributeFile);
+            Assert.FileExists(result, cacheFile);
 
-            var thumbPrint = GetThumbPrint(generatedAttributeFile);
+            var cacheFilethumbPrint = GetThumbPrint(cacheFile);
+            var outputFilethumbPrint = GetThumbPrint(outputFile);
 
-            result = await DotnetMSBuild("Build");
+            // Couple rounds of incremental builds.
+            await AssertIncrementalBuild();
+            await AssertIncrementalBuild();
+            await AssertIncrementalBuild();
 
-            Assert.BuildPassed(result);
+            async Task AssertIncrementalBuild()
+            {
+                result = await DotnetMSBuild("Build");
 
-            Assert.FileExists(result, generatedAttributeFile);
+                Assert.BuildPassed(result);
-            Assert.Equal(thumbPrint, GetThumbPrint(generatedAttributeFile));
+
+                Assert.FileDoesNotExist(result, generatedAttributeFile);
+                Assert.FileExists(result, cacheFile);
+                Assert.Equal(cacheFilethumbPrint, GetThumbPrint(cacheFile));
+                Assert.Equal(outputFilethumbPrint, GetThumbPrint(outputFile));
+            }
         }
     }
 }