Make RazorCodeGen track file renames \ deletes

Fixes #1810

src/Microsoft.AspNetCore.Razor.Design/build/netstandard2.0/Microsoft.AspNetCore.Razor.Design.targets

@@ -91,10 +91,34 @@
     </ItemGroup>
   </Target>
 
+   <Target Name="_RazorCreateSourceHashFiles" DependsOnTargets="_RazorResolveSourceFiles">
+    <PropertyGroup>
+      <_RazorSourcesHashFile>$(IntermediateOutputPath)$(MSBuildProjectName).RazorSourceHash.cache</_RazorSourcesHashFile>
+    </PropertyGroup>
+
+    <Hash ItemsToHash="@(RazorCompile)">
+      <Output TaskParameter="HashResult" PropertyName="_RazorSourcesHash" />
+    </Hash>
+
+    <MakeDir
+      Directories="$(IntermediateOutputPath)"
+      Condition="!Exists('$(IntermediateOutputPath)')" />
+
+    <WriteLinesToFile
+      Lines="$(_RazorSourcesHash)"
+      File="$(_RazorSourcesHashFile)"
+      Overwrite="True"
+      WriteOnlyWhenDifferent="True" />
+
+    <ItemGroup>
+      <FileWrites Include="$(_RazorSourcesHashFile)" />
+    </ItemGroup>
+  </Target>
+
   <Target
     Name="RazorCoreGenerate"
-    DependsOnTargets="_RazorResolveSourceFiles;_RazorResolveTagHelpers"
+    DependsOnTargets="_RazorResolveSourceFiles;_RazorCreateSourceHashFiles;_RazorResolveTagHelpers"
-    Inputs="$(MSBuildAllProjects);@(RazorCompile);$(_RazorTagHelperOutputCache)"
+    Inputs="$(MSBuildAllProjects);$(_RazorSourcesHashFile);@(RazorCompile);$(_RazorTagHelperOutputCache)"
     Outputs="@(_RazorGenerated)">
 
     <RemoveDir
@@ -235,4 +259,4 @@
       DestinationFolder="$(OutDir)"
       SkipUnchangedFiles="true"/>
   </Target>
-</Project>
+</Project>

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

@@ -19,7 +19,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             if (result == null)
             {
                 throw new ArgumentNullException(nameof(result));
-            };
+            }
 
             if (result.ExitCode != 0)
             {
@@ -259,4 +259,4 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             protected override string Heading => $"File: '{FilePath}' was found, but should not exist.";
         }
     }
-}
+}

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

@@ -0,0 +1,44 @@
+// 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.Security.Cryptography;
+
+namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
+{
+    public class FileThumbPrint : IEquatable<FileThumbPrint>
+    {
+        private FileThumbPrint(DateTime lastWriteTimeUtc, string hash)
+        {
+            LastWriteTimeUtc = lastWriteTimeUtc;
+            Hash = hash;
+        }
+
+        public DateTime LastWriteTimeUtc { get; }
+
+        public string Hash { get; }
+
+        public static FileThumbPrint Create(string path)
+        {
+            byte[] hashBytes;
+            using (var sha1 = SHA1.Create())
+            using (var fileStream = File.OpenRead(path))
+            {
+                hashBytes = sha1.ComputeHash(fileStream);
+            }
+
+            var hash = Convert.ToBase64String(hashBytes);
+            var lastWriteTimeUtc = File.GetLastWriteTimeUtc(path);
+            return new FileThumbPrint(lastWriteTimeUtc, hash);
+        }
+
+        public bool Equals(FileThumbPrint other)
+        {
+            return LastWriteTimeUtc == other.LastWriteTimeUtc &&
+                string.Equals(Hash, other.Hash, StringComparison.Ordinal);
+        }
+
+        public override int GetHashCode() => LastWriteTimeUtc.GetHashCode();
+    }
+}

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

@@ -2,10 +2,12 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
+using Moq;
 
 namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 {
@@ -68,5 +70,37 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
             File.WriteAllText(filePath, content, Encoding.UTF8);
         }
+
+        /// <summary>
+        /// Locks all files, discovered at the time of method invocation, under the
+        /// specified <paramref name="directory" /> from reads or writes.
+        /// </summary>
+        public IDisposable LockDirectory(string directory)
+        {
+            directory = Path.Combine(Project.DirectoryPath, directory);
+            var disposables = new List<IDisposable>();
+            foreach (var file in Directory.EnumerateFiles(directory, "*", SearchOption.AllDirectories))
+            {
+                disposables.Add(LockFile(file));
+            }
+
+            var disposable = new Mock<IDisposable>();
+            disposable.Setup(d => d.Dispose())
+                .Callback(() => disposables.ForEach(d => d.Dispose()));
+
+            return disposable.Object;
+        }
+
+        public IDisposable LockFile(string path)
+        {
+            path = Path.Combine(Project.DirectoryPath, path);
+            return File.Open(path, FileMode.Open, FileAccess.Read, FileShare.None);
+        }
+
+        public FileThumbPrint GetThumbPrint(string path)
+        {
+            path = Path.Combine(Project.DirectoryPath, path);
+            return FileThumbPrint.Create(path);
+        }
     }
 }

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

@@ -2,18 +2,27 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Reflection;
 using System.Threading;
 using Microsoft.AspNetCore.Testing;
+using Moq;
 
 namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 {
     internal class ProjectDirectory : IDisposable
     {
+#if PRESERVE_WORKING_DIRECTORY
+        public bool PreserveWorkingDirectory { get; set; } = true;
+#else
+        public bool PreserveWorkingDirectory { get; set; }
+#endif
+
         public static ProjectDirectory Create(string projectName)
         {
-            var destinationPath = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName());
+            var destinationPath = Path.Combine(Path.GetTempPath(), "Razor", Path.GetRandomFileName());
             Directory.CreateDirectory(destinationPath);
 
             try
@@ -80,6 +89,7 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 #else
 #error Unknown Configuration
 #endif
+
                 var text = $@"
 <Project>
   <PropertyGroup>
@@ -113,7 +123,14 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
         public void Dispose()
         {
-            CleanupDirectory(DirectoryPath);
+            if (PreserveWorkingDirectory)
+            {
+                Console.WriteLine($"Skipping deletion of working directory {DirectoryPath}");
+            }
+            else
+            {
+                CleanupDirectory(DirectoryPath);
+            }
         }
 
         private static void CleanupDirectory(string filePath)

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

@@ -1,6 +1,9 @@
 // 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.Threading.Tasks;
 using Xunit;
 
@@ -8,11 +11,13 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 {
     public class RazorGenerateIntegrationTest : MSBuildIntegrationTestBase
     {
+        private const string RazorGenerateTarget = "RazorGenerate";
+
         [Fact]
         [InitializeTestProject("SimpleMvc")]
         public async Task RazorGenerate_Success_GeneratesFilesOnDisk()
         {
-            var result = await DotnetMSBuild("RazorGenerate");
+            var result = await DotnetMSBuild(RazorGenerateTarget);
 
             Assert.BuildPassed(result);
 
@@ -52,5 +57,126 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             // The file should still be generated even if we had a Razor syntax error.
             Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Index.cs");
         }
+
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task RazorGenerate_BuildsIncrementally()
+        {
+            // Act - 1
+            var result = await DotnetMSBuild(RazorGenerateTarget);
+            var generatedFile = Path.Combine(Project.DirectoryPath, RazorIntermediateOutputPath, "Views", "Home", "About.cs");
+
+            // Assert - 1
+            Assert.BuildPassed(result);
+            Assert.FileExists(result, generatedFile);
+            var thumbPrint = GetThumbPrint(generatedFile);
+
+            // Act - 2
+            using (var razorGenDirectoryLock = LockDirectory(RazorIntermediateOutputPath))
+            {
+                result = await DotnetMSBuild(RazorGenerateTarget);
+            }
+
+            // Assert - 2
+            Assert.BuildPassed(result);
+            Assert.FileExists(result, generatedFile);
+            var currentThumbPrint = GetThumbPrint(generatedFile);
+            Assert.Equal(thumbPrint, currentThumbPrint);
+        }
+
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task RazorGenerate_Rebuilds_IfSourcesAreUpdated()
+        {
+            // Act - 1
+            var result = await DotnetMSBuild(RazorGenerateTarget);
+            var file = Path.Combine(Project.DirectoryPath, "Views", "Home", "Contact.cshtml");
+            var generatedFile = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Contact.cs");
+
+            // Assert - 1
+            Assert.BuildPassed(result);
+            var fileThumbPrint = GetThumbPrint(generatedFile);
+
+            // Act - 2
+            // Update the source content and build. We should expect the outputs to be regenerated.
+            // Timestamps on xplat are precise only to a second. Add a delay so we can ensure that MSBuild recognizes the
+            // file change. See https://github.com/dotnet/corefx/issues/26024
+            await Task.Delay(TimeSpan.FromSeconds(1));
+            ReplaceContent("Uodated content", file);
+            result = await DotnetMSBuild(RazorGenerateTarget);
+
+            // Assert - 2
+            Assert.BuildPassed(result);
+            var newThumbPrint = GetThumbPrint(generatedFile);
+            Assert.NotEqual(fileThumbPrint, newThumbPrint);
+        }
+
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task RazorGenerate_Rebuilds_IfOutputFilesAreMissing()
+        {
+            // Act - 1
+            var result = await DotnetMSBuild(RazorGenerateTarget);
+            var file = Path.Combine(Project.DirectoryPath, RazorIntermediateOutputPath, "Views", "Home", "About.cs");
+
+            // Assert - 1
+            Assert.BuildPassed(result);
+            Assert.FileExists(result, file);
+
+            // Act - 2
+            File.Delete(file);
+            result = await DotnetMSBuild(RazorGenerateTarget);
+
+            // Assert - 2
+            Assert.BuildPassed(result);
+            Assert.FileExists(result, file);
+        }
+
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task RazorGenerate_Rebuilds_IfInputFilesAreRenamed()
+        {
+            // Act - 1
+            var result = await DotnetMSBuild(RazorGenerateTarget);
+            var file = Path.Combine(Project.DirectoryPath, "Views", "Home", "Index.cshtml");
+            var renamed = Path.Combine(Project.DirectoryPath, "Views", "Home", "NewIndex.cshtml");
+            var generated = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Index.cs");
+
+            // Assert - 1
+            Assert.BuildPassed(result);
+            Assert.FileExists(result, file);
+            Assert.FileExists(result, generated);
+
+            // Act - 2
+            File.Move(file, renamed);
+            result = await DotnetMSBuild(RazorGenerateTarget);
+
+            // Assert - 2
+            Assert.BuildPassed(result);
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "NewIndex.cs");
+            Assert.FileDoesNotExist(result, generated);
+        }
+
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task RazorGenerate_Rebuilds_IfInputFilesAreDeleted()
+        {
+            // Act - 1
+            var result = await DotnetMSBuild(RazorGenerateTarget);
+            var file = Path.Combine(Project.DirectoryPath, "Views", "Home", "Index.cshtml");
+            var generatedFile = Path.Combine(RazorIntermediateOutputPath, "Views", "Home", "Index.cs");
+
+            // Assert - 1
+            Assert.BuildPassed(result);
+            Assert.FileExists(result, generatedFile);
+
+            // Act - 2
+            File.Delete(file);
+            result = await DotnetMSBuild(RazorGenerateTarget);
+
+            // Assert - 2
+            Assert.BuildPassed(result);
+            Assert.FileDoesNotExist(result, generatedFile);
+        }
     }
 }

test/Microsoft.AspNetCore.Razor.Design.Test/Microsoft.AspNetCore.Razor.Design.Test.csproj

@@ -9,7 +9,7 @@
     --> 
     <TargetFramework>netcoreapp2.0</TargetFramework>
     <PreserveCompilationContext>true</PreserveCompilationContext>
-
+    <DefineConstants Condition="'$(PreserveWorkingDirectory)'=='true'">$(DefineConstants);PRESERVE_WORKING_DIRECTORY</DefineConstants>
     <!-- Copy references locally so that we can use them in the test. -->
     <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
   </PropertyGroup>

test/Microsoft.AspNetCore.Razor.Test.MvcShim/Microsoft.AspNetCore.Razor.Test.MvcShim.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>$(StandardTestTfms);netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>$(StandardTestTfms)</TargetFrameworks>
     <PreserveCompilationContext>true</PreserveCompilationContext>
   </PropertyGroup>