Verify support for reporting errors using MSBuild (#1867)

* Verify support for reporting errors using MSBuild
* Verifies that CSC errors get mapped to the right place

Resolves #1850

src/Microsoft.AspNetCore.Razor.GenerateTool/RunCommand.cs

@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Mvc.Razor.Extensions;
 using Microsoft.AspNetCore.Razor.Language;
@@ -60,7 +59,7 @@ namespace Microsoft.AspNetCore.Razor.GenerateTool
                     success = false;
                     foreach (var error in result.CSharpDocument.Diagnostics)
                     {
-                        Console.Error.WriteLine(error.GetMessage());
+                        Console.Error.WriteLine(error.ToString());
                     }
                 }
 

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

@@ -3,14 +3,17 @@
 
 using System;
 using System.IO;
-using System.Linq;
-using System.Runtime.Serialization;
 using System.Text;
+using System.Text.RegularExpressions;
 
 namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 {
     internal class Assert : Xunit.Assert
     {
+        // Matches `{filename}: error {code}: {message} [{project}]
+        // See https://stackoverflow.com/questions/3441452/msbuild-and-ignorestandarderrorwarningformat/5180353#5180353
+        private static readonly Regex ErrorRegex = new Regex(@"^(?'location'.+): error (?'errorcode'[A-Z0-9]+): (?'message'.+) \[(?'project'.+)\]$");
+
         public static void BuildPassed(MSBuildResult result)
         {
             if (result == null)
@@ -24,6 +27,52 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             }
         }
 
+        public static void BuildError(MSBuildResult result, string errorCode, string location = null)
+        {
+            if (result == null)
+            {
+                throw new ArgumentNullException(nameof(result));
+            }
+
+            // 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];
+                var match = ErrorRegex.Match(line);
+                if (match.Success)
+                {
+                    if (match.Groups["errorcode"].Value != errorCode)
+                    {
+                        continue;
+                    }
+
+                    if (location != null && match.Groups["location"].Value != location)
+                    {
+                        continue;
+                    }
+
+                    // This is a match
+                    return;
+                }
+            }
+
+            throw new BuildErrorMissingException(result, errorCode);
+        }
+
+        public static void BuildFailed(MSBuildResult result)
+        {
+            if (result == null)
+            {
+                throw new ArgumentNullException(nameof(result));
+            };
+
+            if (result.ExitCode == 0)
+            {
+                throw new BuildPassedException(result);
+            }
+        }
+
         public static void FileExists(MSBuildResult result, params string[] paths)
         {
             if (result == null)
@@ -106,6 +155,20 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             }
         }
 
+        private class BuildErrorMissingException : MSBuildXunitException
+        {
+            public BuildErrorMissingException(MSBuildResult result, string errorCode)
+                : base(result)
+            {
+                ErrorCode = errorCode;
+            }
+
+            public string ErrorCode { get; }
+
+            protected override string Heading => $"Error code '{ErrorCode}' was not found.";
+        }
+
+
         private class BuildFailedException : MSBuildXunitException
         {
             public BuildFailedException(MSBuildResult result)
@@ -113,7 +176,17 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             {
             }
 
-            protected override string Heading => "Build failed:";
+            protected override string Heading => "Build failed.";
+        }
+
+        private class BuildPassedException : MSBuildXunitException
+        {
+            public BuildPassedException(MSBuildResult result)
+                : base(result)
+            {
+            }
+
+            protected override string Heading => "Build should have failed, but it passed.";
         }
 
         private class FileMissingException : MSBuildXunitException

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

@@ -19,5 +19,24 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.FileExists(result, OutputPath, "SimpleMvc.dll");
             Assert.FileExists(result, OutputPath, "SimpleMvc.PrecompiledViews.dll");
         }
+
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task Build_ErrorInGeneratedCode_ReportsMSBuildError()
+        {
+            // Introducing a C# semantic error
+            ReplaceContent("@{ var foo = \"\".Substring(\"bleh\"); }", "Views", "Home", "Index.cshtml");
+
+            var result = await DotnetMSBuild("Build", "/p:RazorCompileOnBuild=true");
+
+            Assert.BuildFailed(result);
+
+            // Verifying that the error correctly gets mapped to the original source
+            Assert.BuildError(result, "CS1503", location: Path.Combine("Views", "Home", "Index.cshtml") + "(1,27)");
+
+            // Compilation failed without creating the views assembly
+            Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.dll");
+            Assert.FileDoesNotExist(result, IntermediateOutputPath, "SimpleMvc.PrecompiledViews.dll");
+        }
     }
 }

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

@@ -3,6 +3,7 @@
 
 using System;
 using System.IO;
+using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -46,5 +47,26 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
 
             return MSBuildProcessManager.RunProcessAsync(Project, $"{restoreArgument} /t:{target} /p:Configuration={Configuration} {args}", timeout);
         }
+
+        internal void ReplaceContent(string content, params string[] paths)
+        {
+            if (content == null)
+            {
+                throw new ArgumentNullException(nameof(content));
+            }
+
+            if (paths == null)
+            {
+                throw new ArgumentNullException(nameof(paths));
+            }
+
+            var filePath = Path.Combine(Project.DirectoryPath, Path.Combine(paths));
+            if (!File.Exists(filePath))
+            {
+                throw new InvalidOperationException($"File {filePath} could not be found.");
+            }
+
+            File.WriteAllText(filePath, content, Encoding.UTF8);
+        }
     }
 }

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

@@ -1,8 +1,6 @@
 // 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.IO;
-using System.Linq;
 using System.Threading.Tasks;
 using Xunit;
 
@@ -32,5 +30,27 @@ namespace Microsoft.AspNetCore.Razor.Design.IntegrationTests
             Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Shared", "Error.cs");
             Assert.FileCountEquals(result, 8, RazorIntermediateOutputPath, "*.cs");
         }
+
+        [Fact]
+        [InitializeTestProject("SimpleMvc")]
+        public async Task RazorGenerate_ErrorInRazorFile_ReportsMSBuildError()
+        {
+            // Introducing a syntax error, an unclosed brace
+            ReplaceContent("@{", "Views", "Home", "Index.cshtml");
+
+            var result = await DotnetMSBuild("RazorGenerate");
+
+            Assert.BuildFailed(result);
+
+            // Looks like C:\...\Views\Home\Index.cshtml(1,2): error RZ1006: The code block is missi... [C:\Users\rynowak\AppData\Local\Temp\rwnv03ll.wb0\SimpleMvc.csproj]
+            Assert.BuildError(result, "RZ1006");
+
+            // RazorGenerate should compile the assembly, but not the views.
+            Assert.FileExists(result, IntermediateOutputPath, "SimpleMvc.dll");
+            Assert.FileDoesNotExist(result, IntermediateOutputPath, "SimpleMvc.PrecompiledViews.dll");
+
+            // The file should still be generated even if we had a Razor syntax error.
+            Assert.FileExists(result, RazorIntermediateOutputPath, "Views", "Home", "Index.cs");
+        }
     }
 }