Add DebugHelper to make debugging easier

src/Microsoft.AspNetCore.Razor.Design/Internal/DebugHelper.cs

@@ -0,0 +1,25 @@
+// 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.
+
+#if DEBUG
+using System;
+using System.Diagnostics;
+using System.Linq;
+
+namespace Microsoft.AspNetCore.Razor.Design.Internal
+{
+    public class DebugHelper
+    {
+        public static void HandleDebugSwitch(ref string[] args)
+        {
+            if (args.Length > 0 && string.Equals("--debug", args[0], StringComparison.OrdinalIgnoreCase))
+            {
+                args = args.Skip(1).ToArray();
+                Console.Error.WriteLine("Waiting for debugger to attach. Press ENTER to continue");
+                Console.Error.WriteLine($"Process ID: {Process.GetCurrentProcess().Id}");
+                Console.ReadLine();
+            }
+        }
+    }
+}
+#endif

src/Microsoft.AspNetCore.Razor.Design/Program.cs

@@ -5,6 +5,7 @@ using System;
 using System.Globalization;
 using System.Linq;
 using System.Reflection;
+using Microsoft.AspNetCore.Razor.Design.Internal;
 
 namespace Microsoft.AspNetCore.Razor.Design
 {
@@ -14,6 +15,9 @@ namespace Microsoft.AspNetCore.Razor.Design
 
         public static int Main(string[] args)
         {
+#if DEBUG
+            DebugHelper.HandleDebugSwitch(ref args);
+#endif
             var app = new RazorToolingApplication(ProgramType);
 
             EnsureValidDispatchRecipient(ref args);

src/Microsoft.AspNetCore.Razor.Tools/Internal/ResolveTagHelpersDispatchCommand.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.Collections.Generic;
 using System.Globalization;
 using System.IO;
@@ -86,6 +87,14 @@ namespace Microsoft.AspNetCore.Razor.Tools.Internal
                 dispatchArgs.Add(ProtocolOption.Value());
             }
 
+#if DEBUG
+            var commandLineArgs = Environment.GetCommandLineArgs();
+            if (commandLineArgs.Length > 1 && commandLineArgs[1] == "--debug")
+            {
+                dispatchArgs.Insert(0, commandLineArgs[1]);
+            }
+#endif
+
             var toolName = typeof(Design.Program).GetTypeInfo().Assembly.GetName().Name;
             var dispatchCommand = DotnetToolDispatcher.CreateDispatchCommand(
                 dispatchArgs,
@@ -99,7 +108,11 @@ namespace Microsoft.AspNetCore.Razor.Tools.Internal
             using (var errorWriter = new StringWriter())
             {
                 var commandExitCode = dispatchCommand
+#if DEBUG
+                    .ForwardStdErr(Console.Error)
+#else
                     .ForwardStdErr(errorWriter)
+#endif
                     .ForwardStdOut()
                     .Execute()
                     .ExitCode;

src/Microsoft.AspNetCore.Razor.Tools/Program.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using Microsoft.AspNetCore.Razor.Design;
+using Microsoft.AspNetCore.Razor.Design.Internal;
 using Microsoft.AspNetCore.Razor.Tools.Internal;
 
 namespace Microsoft.AspNetCore.Razor.Tools
@@ -10,6 +11,9 @@ namespace Microsoft.AspNetCore.Razor.Tools
     {
         public static int Main(string[] args)
         {
+#if DEBUG
+            DebugHelper.HandleDebugSwitch(ref args);
+#endif
             var app = new RazorToolingApplication(typeof(Program));
 
             ResolveTagHelpersCommandBase.Register<ResolveTagHelpersDispatchCommand>(app);

test/Microsoft.AspNetCore.Razor.Tools.Test/Infrastructure/ToolTestFixture.cs

@@ -47,7 +47,7 @@ namespace Microsoft.AspNetCore.Razor.Tools.Test.Infrastructure
             var outputWriter = new StringWriter();
 
             var exitCode = command
-                .ForwardStdErr(outputWriter)
+                .ForwardStdErr(Console.Error)
                 .ForwardStdOut(outputWriter)
                 .WorkingDirectory(projectDirectory)
                 .Execute()