Added a message of enabled logs, and their paths.

documentation/wiki/ChangeWaves.md

@@ -31,6 +31,7 @@ Change wave checks around features will be removed in the release that accompani
 
 ### 18.8
 - [RAR task: across multiple input properties, resolve relative paths against the project directory (not the process current directory)](https://github.com/dotnet/msbuild/pull/13319)
+- [Console, parallel console, and terminal loggers print the paths of log files written by registered loggers (e.g. file logger and binary logger) as part of the end-of-build summary.](https://github.com/dotnet/msbuild/pull/13577)
 
 ### 18.7
 - [Copy task retries on ERROR_ACCESS_DENIED on non-Windows platforms to handle transient lock conflicts (e.g. macOS CoW filesystems)](https://github.com/dotnet/msbuild/issues/13463)

src/Build.UnitTests/BackEnd/LoggingServicesLogMethod_Tests.cs

@@ -14,6 +14,7 @@
 using Microsoft.Build.Execution;
 using Microsoft.Build.Framework;
 using Microsoft.Build.Shared;
+using Microsoft.Build.Logging;
 using Shouldly;
 using Xunit;
 using InvalidProjectFileException = Microsoft.Build.Exceptions.InvalidProjectFileException;
@@ -1046,6 +1047,52 @@ public void LogBuildFinished()
             buildEvent = new BuildFinishedEventArgs(string.Empty, null /* no help keyword */, true, service.ProcessedBuildEvent.Timestamp);
             Assert.True(((BuildFinishedEventArgs)service.ProcessedBuildEvent).IsEquivalent(buildEvent));
         }
+        [Fact]
+        public void LogBuildStartedLogsLoggerNames()
+        {
+            ProcessBuildEventHelper service = (ProcessBuildEventHelper)ProcessBuildEventHelper.CreateLoggingService(LoggerMode.Synchronous, 1);
+            ConsoleLogger consoleLogger = new ConsoleLogger();
+            service.RegisterLogger(consoleLogger);
+
+            service.LogBuildStarted();
+            var enabledLogsEvent = service.AllProcessedBuildEvents
+                .OfType<BuildMessageEventArgs>()
+                .FirstOrDefault(e => e.Message?.Contains("ConsoleLogger") == true);
+            enabledLogsEvent.ShouldNotBeNull();
+        }
+
+        [Fact]
+        public void LogFilePathsPresentInFileLog()
+        {
+            using var env = TestEnvironment.Create();
+            var logFilePath = env.ExpectFile(".log").Path;
+
+            var fileLogger = new FileLogger { Parameters = "logfile=" + logFilePath };
+            var mockLogger = new MockLogger();
+
+            using (var collection = new ProjectCollection())
+            {
+                var project = ObjectModelHelpers.CreateInMemoryProject(collection, @"
+            <Project>
+              <Target Name=""Build"" />
+            </Project>");
+                project.Build(new ILogger[] { fileLogger, mockLogger }).ShouldBeTrue();
+            }
+
+            // Check that MockLogger captured a LoggersRegisteredEventArgs containing the file logger path
+            var registeredEvent = mockLogger.AllBuildEvents
+                .OfType<LoggersRegisteredEventArgs>()
+                .FirstOrDefault(e => e.Loggers.Any(l => l.LoggerName == nameof(FileLogger)));
+            registeredEvent.ShouldNotBeNull();
+            var fileLoggerDesc = registeredEvent.Loggers.First(l => l.LoggerName == nameof(FileLogger));
+            var expectedPath = Path.GetFullPath(logFilePath);
+            fileLoggerDesc.OutputFilePaths.ShouldContain(expectedPath);
+            fileLoggerDesc.Parameters.ShouldBe(fileLogger.Parameters);
+
+            // Check the file log itself contains the exact path
+            var fileLogContents = File.ReadAllText(logFilePath);
+            fileLogContents.ShouldContain(expectedPath);
+        }
 
         [Fact]
         public void LogBuildCanceled()
@@ -1795,6 +1842,11 @@ internal sealed class ProcessBuildEventHelper : LoggingService
             /// to verify that a buildEvent was sent to ProcessLoggingEvent.
             /// </summary>
             private BuildEventArgs _processedBuildEvent;
+
+            /// <summary>
+            /// All events processed by ProcessLoggingEvent.
+            /// </summary>
+            internal List<BuildEventArgs> AllProcessedBuildEvents { get; } = new();
             #endregion
             #region Constructor
             /// <summary>
@@ -1857,6 +1909,7 @@ protected internal override void ProcessLoggingEvent(object buildEvent)
                 if (buildEvent is BuildEventArgs buildEventArgs)
                 {
                     _processedBuildEvent = buildEventArgs;
+                    AllProcessedBuildEvents.Add(buildEventArgs);
                 }
                 else if (buildEvent is KeyValuePair<int, BuildEventArgs> kvp)
                 {

src/Build.UnitTests/BackEnd/NodePackets_Tests.cs

@@ -82,6 +82,7 @@ public void VerifyEventType()
             BuildCheckTracingEventArgs buildCheckTracing = new();
             BuildCanceledEventArgs buildCanceled = new("message", DateTime.UtcNow);
             WorkerNodeTelemetryEventArgs workerNodeTelemetry = new();
+            LoggersRegisteredEventArgs loggersRegistered = new(new List<RegisteredLoggerInfo> { new RegisteredLoggerInfo("FileLogger", new[] { @"C:\logs\build.log" }) });
 
             VerifyLoggingPacket(buildFinished, LoggingEventType.BuildFinishedEvent);
             VerifyLoggingPacket(buildStarted, LoggingEventType.BuildStartedEvent);
@@ -119,6 +120,7 @@ public void VerifyEventType()
             VerifyLoggingPacket(buildCheckTracing, LoggingEventType.BuildCheckTracingEvent);
             VerifyLoggingPacket(buildCanceled, LoggingEventType.BuildCanceledEvent);
             VerifyLoggingPacket(workerNodeTelemetry, LoggingEventType.WorkerNodeTelemetryEvent);
+            VerifyLoggingPacket(loggersRegistered, LoggingEventType.LoggersRegisteredEvent);
         }
 
         private static BuildEventContext CreateBuildEventContext()
@@ -321,6 +323,21 @@ public void TestTranslation()
                         BuildEventContext = new BuildEventContext(1, 2, 3, 4, 5, 6, 7)
                     },
                     new GeneratedFileUsedEventArgs("path", "some content"),
+                    new LoggersRegisteredEventArgs(new List<RegisteredLoggerInfo>
+                    {
+                        new RegisteredLoggerInfo("FileLogger", new[] { @"C:\logs\build.log" }),
+                        new RegisteredLoggerInfo("BinaryLogger"),
+                        new RegisteredLoggerInfo(
+                            "ConsoleLogger",
+                            outputFilePaths: null,
+                            verbosity: LoggerVerbosity.Detailed,
+                            parameters: "ShowTimestamp;ShowEventId"),
+                        new RegisteredLoggerInfo(
+                            "MultiFileLogger",
+                            outputFilePaths: new[] { @"C:\logs\a.log", @"C:\logs\b.log" },
+                            verbosity: LoggerVerbosity.Diagnostic,
+                            parameters: "LogFile=a.log;LogFile=b.log"),
+                    }),
                 };
                 foreach (BuildEventArgs arg in testArgs)
                 {

src/Build.UnitTests/BackEnd/TaskHostCallback_Tests.cs

@@ -277,10 +277,13 @@ public void GlobalProperties_ForwardedToAutoEjectedTaskInMultiThreadedMode()
         public void GlobalProperties_UseBuildLevelWhenChangeWaveDisabled()
         {
             using TestEnvironment env = TestEnvironment.Create(_output);
-            env.SetEnvironmentVariable("MSBUILDDISABLEFEATURESFROMVERSION", ChangeWaves.Wave18_6.ToString());
-            string testDir = env.CreateFolder().Path;
+            try
+            {
+                ChangeWaves.ResetStateForTests();
+                env.SetEnvironmentVariable("MSBUILDDISABLEFEATURESFROMVERSION", ChangeWaves.Wave18_6.ToString());
+                string testDir = env.CreateFolder().Path;
 
-            string projectContents = $@"
+                string projectContents = $@"
 <Project>
     <UsingTask TaskName=""{nameof(GetGlobalPropertiesTask)}"" AssemblyFile=""{typeof(GetGlobalPropertiesTask).Assembly.Location}"" />
     <Target Name=""Test"">
@@ -290,32 +293,37 @@ public void GlobalProperties_UseBuildLevelWhenChangeWaveDisabled()
     </Target>
 </Project>";
 
-            string projectFile = Path.Combine(testDir, "Test.proj");
-            File.WriteAllText(projectFile, projectContents);
-
-            // These request-level properties should NOT be forwarded when the wave is disabled
-            var requestGlobalProperties = new Dictionary<string, string?>
-            {
-                ["TestRequestProperty"] = "RequestValue",
-            };
+                string projectFile = Path.Combine(testDir, "Test.proj");
+                File.WriteAllText(projectFile, projectContents);
 
-            var logger = new MockLogger(_output);
-            BuildResult buildResult = BuildManager.DefaultBuildManager.Build(
-                new BuildParameters
+                // These request-level properties should NOT be forwarded when the wave is disabled
+                var requestGlobalProperties = new Dictionary<string, string?>
                 {
-                    MultiThreaded = true,
-                    MaxNodeCount = 4,
-                    Loggers = [logger],
-                    EnableNodeReuse = false,
-                },
-                new BuildRequestData(projectFile, requestGlobalProperties, null, ["Test"], null));
-
-            buildResult.OverallResult.ShouldBe(BuildResultCode.Success);
-
-            // With wave disabled, build-level properties are used (empty in this test),
-            // so request-level properties should NOT appear
-            logger.FullLog.ShouldNotContain("GlobalProperty: TestRequestProperty=RequestValue");
-            logger.FullLog.ShouldContain("GlobalPropertyCount = 0");
+                    ["TestRequestProperty"] = "RequestValue",
+                };
+
+                var logger = new MockLogger(_output);
+                BuildResult buildResult = BuildManager.DefaultBuildManager.Build(
+                    new BuildParameters
+                    {
+                        MultiThreaded = true,
+                        MaxNodeCount = 4,
+                        Loggers = [logger],
+                        EnableNodeReuse = false,
+                    },
+                    new BuildRequestData(projectFile, requestGlobalProperties, null, ["Test"], null));
+
+                buildResult.OverallResult.ShouldBe(BuildResultCode.Success);
+
+                // With wave disabled, build-level properties are used (empty in this test),
+                // so request-level properties should NOT appear
+                logger.FullLog.ShouldNotContain("GlobalProperty: TestRequestProperty=RequestValue");
+                logger.FullLog.ShouldContain("GlobalPropertyCount = 0");
+            }
+            finally
+            {
+                ChangeWaves.ResetStateForTests();
+            }
         }
 
         /// <summary>

src/Build.UnitTests/BuildEventArgsSerialization_Tests.cs

@@ -109,6 +109,33 @@ public void RoundtripBuildCanceledEventArgs()
                 e => e.Timestamp.ToString());
         }
 
+        [Fact]
+        public void RoundtripLoggersRegisteredEventArgs()
+        {
+            var args = new LoggersRegisteredEventArgs(new List<RegisteredLoggerInfo>
+            {
+                new RegisteredLoggerInfo("FileLogger", new[] { @"C:\logs\build.log" }),
+                new RegisteredLoggerInfo("BinaryLogger"),
+                new RegisteredLoggerInfo(
+                    "ConsoleLogger",
+                    outputFilePaths: null,
+                    verbosity: LoggerVerbosity.Detailed,
+                    parameters: "ShowTimestamp;ShowEventId"),
+                new RegisteredLoggerInfo(
+                    "MultiFileLogger",
+                    outputFilePaths: new[] { @"C:\logs\a.log", @"C:\logs\b.log" },
+                    verbosity: LoggerVerbosity.Diagnostic,
+                    parameters: "LogFile=a.log;LogFile=b.log"),
+            });
+
+            Roundtrip(args,
+                e => e.Loggers.Count.ToString(CultureInfo.InvariantCulture),
+                e => string.Join("|", e.Loggers.Select(l => l.LoggerName)),
+                e => string.Join("|", e.Loggers.Select(l => l.Parameters ?? "<null>")),
+                e => string.Join("|", e.Loggers.Select(l => l.Verbosity?.ToString() ?? "<null>")),
+                e => string.Join("|", e.Loggers.Select(l => string.Join(",", l.OutputFilePaths))));
+        }
+
         [Fact]
         public void RoundtripBuildSubmissionStartedEventArgs()
         {

src/Build.UnitTests/ConsoleLogger_Tests.cs

@@ -1961,6 +1961,84 @@ public void TestPrintTargetNamePerMessage()
             actualLog.ShouldContain("t:");
         }
 
+        /// <summary>
+        /// <summary>
+        /// When the loggers print their output paths feature wave is enabled (default),
+        /// the ParallelConsoleLogger end-of-build summary should list each registered logger
+        /// that wrote to a file along with its output path(s).
+        /// </summary>
+        [Fact]
+        public void LogFileOutputPaths_PrintedInSummary_WhenWaveEnabled()
+        {
+            try
+            {
+                ChangeWaves.ResetStateForTests();
+
+                SimulatedConsole sc = new SimulatedConsole();
+                ParallelConsoleLogger cl = new ParallelConsoleLogger(LoggerVerbosity.Normal, sc.Write, null, null);
+                EventSourceSink es = new EventSourceSink();
+                cl.Initialize(es);
+
+                BuildStartedEventArgs bsea = new BuildStartedEventArgs("bs", null);
+                cl.BuildStartedHandler(null, bsea);
+
+                LoggersRegisteredEventArgs lrea = new LoggersRegisteredEventArgs(new List<RegisteredLoggerInfo>
+                {
+                    new RegisteredLoggerInfo("FileLogger", new[] { @"C:\logs\build.log" }),
+                });
+                cl.StatusEventHandler(null, lrea);
+
+                BuildFinishedEventArgs bfea = new BuildFinishedEventArgs("bf", null, true);
+                cl.BuildFinishedHandler(null, bfea);
+
+                sc.ToString().ShouldContain("FileLogger");
+                sc.ToString().ShouldContain(@"C:\logs\build.log");
+            }
+            finally
+            {
+                ChangeWaves.ResetStateForTests();
+            }
+        }
+
+        /// <summary>
+        /// When the loggers print their output paths feature wave is disabled
+        /// via MSBUILDDISABLEFEATURESFROMVERSION, the ParallelConsoleLogger summary
+        /// must preserve the legacy behavior and NOT print logger output paths.
+        /// </summary>
+        [Fact]
+        public void LogFileOutputPaths_NotPrintedInSummary_WhenWaveDisabled()
+        {
+            using TestEnvironment env = TestEnvironment.Create();
+            try
+            {
+                ChangeWaves.ResetStateForTests();
+                env.SetEnvironmentVariable("MSBUILDDISABLEFEATURESFROMVERSION", ChangeWaves.Wave18_8.ToString());
+
+                SimulatedConsole sc = new SimulatedConsole();
+                ParallelConsoleLogger cl = new ParallelConsoleLogger(LoggerVerbosity.Normal, sc.Write, null, null);
+                EventSourceSink es = new EventSourceSink();
+                cl.Initialize(es);
+
+                BuildStartedEventArgs bsea = new BuildStartedEventArgs("bs", null);
+                cl.BuildStartedHandler(null, bsea);
+
+                LoggersRegisteredEventArgs lrea = new LoggersRegisteredEventArgs(new List<RegisteredLoggerInfo>
+                {
+                    new RegisteredLoggerInfo("FileLogger", new[] { @"C:\logs\build.log" }),
+                });
+                cl.StatusEventHandler(null, lrea);
+
+                BuildFinishedEventArgs bfea = new BuildFinishedEventArgs("bf", null, true);
+                cl.BuildFinishedHandler(null, bfea);
+
+                sc.ToString().ShouldNotContain(@"C:\logs\build.log");
+            }
+            finally
+            {
+                ChangeWaves.ResetStateForTests();
+            }
+        }
+
         /// <summary>
         /// Check to see what kind of device we are outputting the log to, is it a character device, a file, or something else
         /// this can be used by loggers to modify their outputs based on the device they are writing to

src/Build.UnitTests/Graph/ResultCacheBasedBuilds_Tests.cs

@@ -68,7 +68,7 @@ public void InvalidCacheFilesShouldLogError(byte[] cacheContents)
             result.OverallResult.ShouldBe(BuildResultCode.Failure);
 
             _logger.FullLog.ShouldContain("MSB4256:");
-            _logger.AllBuildEvents.Count.ShouldBe(6);
+            _logger.AllBuildEvents.Count.ShouldBe(8);
             _logger.ErrorCount.ShouldBe(1);
         }
 
@@ -564,8 +564,8 @@ public void NonExistingInputResultsCacheShouldLogError()
 
             result.OverallResult.ShouldBe(BuildResultCode.Failure);
 
-            _logger.AllBuildEvents.Count.ShouldBe(6);
-            _logger.Errors.First().Message.ShouldContain("MSB4255:");
+                        _logger.AllBuildEvents.Count.ShouldBe(8);
+                        _logger.Errors.First().Message.ShouldContain("MSB4255:");
             _logger.Errors.First().Message.ShouldContain("FileDoesNotExist1");
             _logger.Errors.First().Message.ShouldContain("FileDoesNotExist2");
             _logger.ErrorCount.ShouldBe(1);