Deprecate binfmt in build event args

eng/dependabot/Packages.props

@@ -13,6 +13,9 @@
     <PackageVersion Include="BenchmarkDotNet" Version="0.13.1" />
     <PackageVersion Update="BenchmarkDotNet" Condition="'$(BenchmarkDotNetVersion)' != ''" Version="$(BenchmarkDotNetVersion)" />
 
+    <PackageVersion Include="FluentAssertions" Version="6.11.0" />
+    <PackageVersion Update="FluentAssertions" Condition="'$(FluentAssertionsVersion)' != ''" Version="$(FluentAssertionsVersion)" />
+
     <PackageVersion Include="LargeAddressAware" Version="1.0.5" />
     <PackageVersion Update="LargeAddressAware" Condition="'$(LargeAddressAwareVersion)' != ''" Version="$(LargeAddressAwareVersion)" />
 

src/Build.UnitTests/BackEnd/BuildManager_Logging_Tests.cs

@@ -0,0 +1,140 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Build.BackEnd.Logging;
+using Microsoft.Build.Evaluation;
+using Microsoft.Build.Execution;
+using Microsoft.Build.Framework;
+using Microsoft.Build.Shared;
+using Microsoft.Build.UnitTests;
+using Shouldly;
+using Xunit;
+using Xunit.Abstractions;
+using static Microsoft.Build.UnitTests.ObjectModelHelpers;
+
+#nullable disable
+
+namespace Microsoft.Build.Engine.UnitTests.BackEnd
+{
+    public class BuildManager_Logging_Tests : IDisposable
+    {
+        /// <summary>
+        /// The mock logger for testing.
+        /// </summary>
+        private readonly MockLogger _logger;
+
+        /// <summary>
+        /// The standard build manager for each test.
+        /// </summary>
+        private readonly BuildManager _buildManager;
+
+        /// <summary>
+        /// The project collection used.
+        /// </summary>
+        private readonly ProjectCollection _projectCollection;
+
+        private readonly TestEnvironment _env;
+        private readonly ITestOutputHelper _output;
+
+        /// <summary>
+        /// SetUp
+        /// </summary>
+        public BuildManager_Logging_Tests(ITestOutputHelper output)
+        {
+            _output = output;
+            // Ensure that any previous tests which may have been using the default BuildManager do not conflict with us.
+            BuildManager.DefaultBuildManager.Dispose();
+
+            _logger = new MockLogger(output);
+            _buildManager = new BuildManager();
+            _projectCollection = new ProjectCollection();
+
+            _env = TestEnvironment.Create(output);
+        }
+
+        [Fact]
+        public void Build_WithCustomBuildArgs_EnvVariableSet()
+        {
+            const string mainProject = @"
+<Project>
+
+  <Target Name=`MainTarget`>
+    <MSBuild Projects=`{0}` Targets=`ChildTarget` />
+  </Target>
+
+</Project>";
+
+            string childProjectWithCustomBuildEvent = $@"
+<Project>
+
+    <UsingTask TaskName=""CustomBuildEventTask"" AssemblyFile=""{Assembly.GetExecutingAssembly().Location}"" />
+    <Target Name=`ChildTarget`>
+        <CustomBuildEventTask />
+    </Target>
+
+</Project>";
+
+            var testFiles = _env.CreateTestProjectWithFiles(string.Empty, new[] { "main", "child1" }, string.Empty);
+
+            ILoggingService service = LoggingService.CreateLoggingService(LoggerMode.Synchronous, 1);
+            service.RegisterLogger(_logger);
+
+            _env.SetEnvironmentVariable("MSBUILDCUSTOMBUILDEVENTWARNING", "1");
+
+            _buildManager.BeginBuild(BuildParameters);
+
+            try
+            {
+                var child1ProjectPath = testFiles.CreatedFiles[1];
+                var cleanedUpChildContents = CleanupFileContents(childProjectWithCustomBuildEvent);
+                File.WriteAllText(child1ProjectPath, cleanedUpChildContents);
+
+                var mainProjectPath = testFiles.CreatedFiles[0];
+                var cleanedUpMainContents = CleanupFileContents(string.Format(mainProject, child1ProjectPath));
+                File.WriteAllText(mainProjectPath, cleanedUpMainContents);
+
+                var buildRequestData = new BuildRequestData(
+                   mainProjectPath,
+                   new Dictionary<string, string>(),
+                   MSBuildConstants.CurrentToolsVersion,
+                   new[] { "MainTarget" },
+                   null);
+
+                var submission = _buildManager.PendBuildRequest(buildRequestData);
+
+                var result = submission.Execute();
+
+                var allEvents = _logger.AllBuildEvents;
+
+                allEvents.OfType<BuildWarningEventArgs>().ShouldHaveSingleItem();
+                allEvents.First(x => x is BuildWarningEventArgs).Message.ShouldContain("MyCustomBuildEventArgs");
+            }
+            finally
+            {
+                _buildManager.EndBuild();
+            }
+        }
+
+        private BuildParameters BuildParameters => new BuildParameters(_projectCollection)
+        {
+            DisableInProcNode = true,
+            EnableNodeReuse = false,
+            Loggers = new ILogger[] { _logger }
+        };
+
+        /// <summary>
+        /// TearDown
+        /// </summary>
+        public void Dispose()
+        {
+            _buildManager.Dispose();
+            _projectCollection.Dispose();
+            _env.Dispose();
+        }
+    }
+}

src/Build.UnitTests/BackEnd/CustomBuildEventTask.cs

@@ -0,0 +1,25 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using Microsoft.Build.Framework;
+using Microsoft.Build.Utilities;
+
+#nullable disable
+
+namespace Microsoft.Build.UnitTests
+{
+    public class CustomBuildEventTask : Task
+    {
+        public override bool Execute()
+        {
+            MyCustomBuildEventArgs customBuildEvent = new() { RawMessage = "A message from MyCustomBuildEventArgs" };
+            BuildEngine.LogCustomEvent(customBuildEvent);
+
+            return true;
+        }
+
+        [Serializable]
+        public sealed class MyCustomBuildEventArgs : CustomBuildEventArgs { }
+    }
+}