Validate binding redirects (#7153)

Fixes #7078

Context
If our binding redirects are off from the packages we actually ship, that can cause problems downstream when we try to integrate with anything other than MSBuild. This ensures they are correct with certain exceptions specified in a comment.

Changes Made
Added a post-build (and tests) validation step.

src/MSBuild/MSBuild.csproj

@@ -330,4 +330,14 @@
 
   </Target>
 
+  <UsingTask TaskName="ValidateMSBuildPackageDependencyVersions" TaskFactory="RoslynCodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll">
+    <Task>
+      <Code Source="ValidateMSBuildPackageDependencyVersions.cs" Language="cs" />
+    </Task>
+  </UsingTask>
+
+  <Target Name="ValidateMSBuildPackageDependencyVersions" BeforeTargets="AfterBuild" Condition="'$(TargetFrameworkIdentifier)' == '.NETFramework'" >
+    <ValidateMSBuildPackageDependencyVersions AppConfig="@(AppConfigWithTargetPath)" AssemblyPath="$(OutputPath)" />
+  </Target>
+
 </Project>

src/MSBuild/ValidateMSBuildPackageDependencyVersions.cs

@@ -0,0 +1,64 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using Microsoft.Build.Framework;
+using Microsoft.Build.Utilities;
+using System;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Xml;
+namespace MSBuild
+{
+    public class ValidateMSBuildPackageDependencyVersions : Task
+    {
+        [Required]
+        public string AppConfig { get; set; }
+        [Required]
+        public string AssemblyPath { get; set; }
+
+        // Microsoft.Build.Conversion.Core and Microsoft.Build.Engine are deprecated, but they're still used in VS for now. This project doesn't directly reference them, so they don't appear in its output directory.
+        // Microsoft.NET.StringTools uses API not available in net35, but since we need it to work for TaskHosts as well, there are simpler versions implemented for that. Ensure it's the right version.
+        // Microsoft.Activities.Build and XamlBuildTask are loaded within an AppDomain in the XamlBuildTask after having been loaded from the GAC elsewhere. See https://github.com/dotnet/msbuild/pull/856
+        private string[] assembliesToIgnore = { "Microsoft.Build.Conversion.Core", "Microsoft.NET.StringTools.net35", "Microsoft.Build.Engine", "Microsoft.Activities.Build", "XamlBuildTask" };
+
+        public override bool Execute()
+        {
+            XmlDocument doc = new XmlDocument();
+            doc.Load(AppConfig);
+            XmlNamespaceManager namespaceManager = new(doc.NameTable);
+            namespaceManager.AddNamespace("asm", "urn:schemas-microsoft-com:asm.v1");
+            bool foundSystemValueTuple = false;
+            foreach (XmlElement dependentAssemblyElement in doc.DocumentElement.SelectNodes("/configuration/runtime/asm:assemblyBinding/asm:dependentAssembly[asm:assemblyIdentity][asm:bindingRedirect]", namespaceManager))
+            {
+                string name = (dependentAssemblyElement.SelectSingleNode("asm:assemblyIdentity", namespaceManager) as XmlElement).GetAttribute("name");
+                string version = (dependentAssemblyElement.SelectSingleNode("asm:bindingRedirect", namespaceManager) as XmlElement).GetAttribute("newVersion");
+                if (!string.IsNullOrEmpty(name) && !string.IsNullOrEmpty(version) && !assembliesToIgnore.Contains(name, StringComparer.OrdinalIgnoreCase))
+                {
+                    string path = Path.Combine(AssemblyPath, name + ".dll");
+                    string assemblyVersion = AssemblyName.GetAssemblyName(path).Version.ToString();
+                    if (!version.Equals(assemblyVersion))
+                    {
+                        // Ensure that the binding redirect is to the GAC version, but
+                        // we still ship the version we explicitly reference to let
+                        // API consumers bind to it at runtime.
+                        // See https://github.com/dotnet/msbuild/issues/6976.
+                        if (String.Equals(name, "System.ValueTuple", StringComparison.OrdinalIgnoreCase) && String.Equals(version, "4.0.0.0") && String.Equals(assemblyVersion, "4.0.3.0"))
+                        {
+                            foundSystemValueTuple = true;
+                        }
+                        else
+                        {
+                            Log.LogError($"Binding redirect for '{name}' redirects to a different version ({version}) than MSBuild ships ({assemblyVersion}).");
+                        }
+                    }
+                }
+            }
+            if (!foundSystemValueTuple)
+            {
+                Log.LogError("Binding redirect for 'System.ValueTuple' missing.");
+            }
+            return !Log.HasLoggedErrors;
+        }
+    }
+}

src/MSBuild/app.amd64.config

@@ -54,7 +54,7 @@
         <!-- Redirects for assemblies redistributed by MSBuild (in the .vsix). -->
         <dependentAssembly>
           <assemblyIdentity name="Microsoft.Bcl.AsyncInterfaces" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
-          <bindingRedirect oldVersion="0.0.0.0-1.0.0.0" newVersion="1.0.0.0" />
+          <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
         </dependentAssembly>
         <dependentAssembly>
           <assemblyIdentity name="Microsoft.NET.StringTools" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />

src/MSBuild/app.config

@@ -45,7 +45,7 @@
         <!-- Redirects for assemblies redistributed by MSBuild (in the .vsix). -->
         <dependentAssembly>
           <assemblyIdentity name="Microsoft.Bcl.AsyncInterfaces" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
-          <bindingRedirect oldVersion="0.0.0.0-1.0.0.0" newVersion="1.0.0.0" />
+          <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
         </dependentAssembly>
         <dependentAssembly>
           <assemblyIdentity name="Microsoft.NET.StringTools" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />