Extend property assignment event (The feature is opted-out by default)

src/Build.UnitTests/BuildEventArgsSerialization_Tests.cs

@@ -881,8 +881,11 @@ public void RoundTripPropertyReassignmentEventArgs()
                 propertyName: "a",
                 previousValue: "b",
                 newValue: "c",
-                location: "d",
-                message: "Property reassignment: $(a)=\"c\" (previous value: \"b\") at d",
+                location: null,
+                file: "file.cs",
+                line: 10,
+                column: 20,
+                message: "Property reassignment: $(a)=\"c\" (previous value: \"b\") at file.cs (10,20)",
                 helpKeyword: "e",
                 senderName: "f");
 
@@ -900,8 +903,8 @@ public void RoundTripPropertyReassignmentEventArgs()
         public void UninitializedPropertyReadEventArgs()
         {
             var args = new UninitializedPropertyReadEventArgs(
-                propertyName: Guid.NewGuid().ToString(),
-                message: Guid.NewGuid().ToString(),
+                propertyName: "a",
+                message: "Read uninitialized property \"a\"",
                 helpKeyword: Guid.NewGuid().ToString(),
                 senderName: Guid.NewGuid().ToString());
 
@@ -916,17 +919,22 @@ public void UninitializedPropertyReadEventArgs()
         public void PropertyInitialValueEventArgs()
         {
             var args = new PropertyInitialValueSetEventArgs(
-                propertyName: Guid.NewGuid().ToString(),
-                propertyValue: Guid.NewGuid().ToString(),
-                propertySource: Guid.NewGuid().ToString(),
-                message: Guid.NewGuid().ToString(),
+                propertyName: "a",
+                propertyValue: "b",
+                propertySource: null,
+                file: "file.cs",
+                line: 10,
+                column: 20,
+                message: "Property initial value: $(a)=\"b\" Source: file.cs (10,20)",
                 helpKeyword: Guid.NewGuid().ToString(),
                 senderName: Guid.NewGuid().ToString());
 
             Roundtrip(args,
                 e => e.PropertyName,
                 e => e.PropertyValue,
-                e => e.PropertySource,
+                e => e.File,
+                e => e.LineNumber.ToString(),
+                e => e.ColumnNumber.ToString(),
                 e => e.Message,
                 e => e.HelpKeyword,
                 e => e.SenderName);

src/Build.UnitTests/Evaluation/Evaluator_Tests.cs

@@ -4708,7 +4708,7 @@ public void VerifyPropertyTrackingLoggingDefault()
             // Having just environment variables defined should default to nothing being logged except one environment variable read.
             VerifyPropertyTrackingLoggingScenario(
                 null,
-                logger =>
+                 (logger, _) =>
                 {
                     logger
                         .AllBuildEvents
@@ -4740,7 +4740,7 @@ public void VerifyPropertyTrackingLoggingPropertyReassignment()
         {
             VerifyPropertyTrackingLoggingScenario(
                 "1",
-                logger =>
+                (logger, _) =>
                 {
                     logger
                         .AllBuildEvents
@@ -4771,7 +4771,7 @@ public void VerifyPropertyTrackingLoggingNone()
         {
             this.VerifyPropertyTrackingLoggingScenario(
                 "0",
-                logger =>
+                 (logger, _) =>
                 {
                     logger
                         .AllBuildEvents
@@ -4803,7 +4803,7 @@ public void VerifyPropertyTrackingLoggingPropertyInitialValue()
         {
             this.VerifyPropertyTrackingLoggingScenario(
                 "2",
-                logger =>
+                (logger, projectPath) =>
                 {
                     logger
                         .AllBuildEvents
@@ -4829,23 +4829,23 @@ public void VerifyPropertyTrackingLoggingPropertyInitialValue()
 
                     // Verify logging of property initial values.
                     propertyInitialValueMap.ShouldContainKey("Prop");
-                    propertyInitialValueMap["Prop"].PropertySource.ShouldBe("Xml");
+                    propertyInitialValueMap["Prop"].File.ShouldBe(projectPath);
                     propertyInitialValueMap["Prop"].PropertyValue.ShouldBe(string.Empty);
 
                     propertyInitialValueMap.ShouldContainKey("EnvVar");
-                    propertyInitialValueMap["EnvVar"].PropertySource.ShouldBe("Xml");
+                    propertyInitialValueMap["EnvVar"].File.ShouldBe(projectPath);
                     propertyInitialValueMap["EnvVar"].PropertyValue.ShouldBe("It's also Defined!");
 
                     propertyInitialValueMap.ShouldContainKey("DEFINED_ENVIRONMENT_VARIABLE");
                     propertyInitialValueMap["DEFINED_ENVIRONMENT_VARIABLE"].PropertySource.ShouldBe("EnvironmentVariable");
                     propertyInitialValueMap["DEFINED_ENVIRONMENT_VARIABLE"].PropertyValue.ShouldBe("It's Defined!");
 
                     propertyInitialValueMap.ShouldContainKey("NotEnvVarRead");
-                    propertyInitialValueMap["NotEnvVarRead"].PropertySource.ShouldBe("Xml");
+                    propertyInitialValueMap["NotEnvVarRead"].File.ShouldBe(projectPath);
                     propertyInitialValueMap["NotEnvVarRead"].PropertyValue.ShouldBe("Overwritten!");
 
                     propertyInitialValueMap.ShouldContainKey("Prop2");
-                    propertyInitialValueMap["Prop2"].PropertySource.ShouldBe("Xml");
+                    propertyInitialValueMap["Prop2"].File.ShouldBe(projectPath);
                     propertyInitialValueMap["Prop2"].PropertyValue.ShouldBe("Value1");
                 });
         }
@@ -4855,7 +4855,7 @@ public void VerifyPropertyTrackingLoggingEnvironmentVariableRead()
         {
             this.VerifyPropertyTrackingLoggingScenario(
                 "4",
-                logger =>
+                (logger, _) =>
                 {
                     logger
                         .AllBuildEvents
@@ -4889,7 +4889,7 @@ public void VerifyPropertyTrackingLoggingUninitializedPropertyRead()
         {
             this.VerifyPropertyTrackingLoggingScenario(
                 "8",
-                logger =>
+                (logger, _) =>
                 {
                     logger
                         .AllBuildEvents
@@ -4920,7 +4920,7 @@ public void VerifyPropertyTrackingLoggingAll()
         {
             this.VerifyPropertyTrackingLoggingScenario(
                 "15",
-                logger =>
+                (logger, projectPath) =>
                 {
                     logger
                         .AllBuildEvents
@@ -4949,23 +4949,23 @@ public void VerifyPropertyTrackingLoggingAll()
 
                     // Verify logging of property initial values.
                     propertyInitialValueMap.ShouldContainKey("Prop");
-                    propertyInitialValueMap["Prop"].PropertySource.ShouldBe("Xml");
+                    propertyInitialValueMap["Prop"].File.ShouldBe(projectPath);
                     propertyInitialValueMap["Prop"].PropertyValue.ShouldBe(string.Empty);
 
                     propertyInitialValueMap.ShouldContainKey("EnvVar");
-                    propertyInitialValueMap["EnvVar"].PropertySource.ShouldBe("Xml");
+                    propertyInitialValueMap["EnvVar"].File.ShouldBe(projectPath);
                     propertyInitialValueMap["EnvVar"].PropertyValue.ShouldBe("It's also Defined!");
 
                     propertyInitialValueMap.ShouldContainKey("DEFINED_ENVIRONMENT_VARIABLE");
                     propertyInitialValueMap["DEFINED_ENVIRONMENT_VARIABLE"].PropertySource.ShouldBe("EnvironmentVariable");
                     propertyInitialValueMap["DEFINED_ENVIRONMENT_VARIABLE"].PropertyValue.ShouldBe("It's Defined!");
 
                     propertyInitialValueMap.ShouldContainKey("NotEnvVarRead");
-                    propertyInitialValueMap["NotEnvVarRead"].PropertySource.ShouldBe("Xml");
+                    propertyInitialValueMap["NotEnvVarRead"].File.ShouldBe(projectPath);
                     propertyInitialValueMap["NotEnvVarRead"].PropertyValue.ShouldBe("Overwritten!");
 
                     propertyInitialValueMap.ShouldContainKey("Prop2");
-                    propertyInitialValueMap["Prop2"].PropertySource.ShouldBe("Xml");
+                    propertyInitialValueMap["Prop2"].File.ShouldBe(projectPath);
                     propertyInitialValueMap["Prop2"].PropertyValue.ShouldBe("Value1");
                 });
         }
@@ -4987,7 +4987,7 @@ public void VerifyGetTypeEvaluationBlocked()
                 new Project(XmlReader.Create(new StringReader(projectContents)), null, "Fake", fakeProjectCollection));
         }
 
-        private void VerifyPropertyTrackingLoggingScenario(string envVarValue, Action<MockLogger> loggerEvaluatorAction)
+        private void VerifyPropertyTrackingLoggingScenario(string envVarValue, Action<MockLogger, string> loggerEvaluatorAction)
         {
             // The default is that only reassignments are logged.
 
@@ -5026,7 +5026,7 @@ private void VerifyPropertyTrackingLoggingScenario(string envVarValue, Action<Mo
 
                 project.Build().ShouldBeTrue();
 
-                loggerEvaluatorAction?.Invoke(logger);
+                loggerEvaluatorAction?.Invoke(logger, tempPath.Path);
             }
         }
 

src/Build/BackEnd/BuildManager/BuildParameters.cs

@@ -146,6 +146,11 @@ public class BuildParameters : ITranslatable
         /// </summary>
         private PropertyDictionary<ProjectPropertyInstance> _globalProperties = new PropertyDictionary<ProjectPropertyInstance>();
 
+        /// <summary>
+        /// Properties passed from the command line (e.g. by using /p:).
+        /// </summary>
+        private HashSet<string> _propertiesFromCommandLine;
+
         /// <summary>
         /// The loggers.
         /// </summary>
@@ -250,6 +255,7 @@ public BuildParameters(ProjectCollection projectCollection)
             _defaultToolsVersion = projectCollection.DefaultToolsVersion;
 
             _globalProperties = new PropertyDictionary<ProjectPropertyInstance>(projectCollection.GlobalPropertiesCollection);
+            _propertiesFromCommandLine = projectCollection.PropertiesFromCommandLine;
         }
 
         /// <summary>
@@ -279,6 +285,7 @@ internal BuildParameters(BuildParameters other, bool resetEnvironment = false)
             _environmentProperties = other._environmentProperties != null ? new PropertyDictionary<ProjectPropertyInstance>(other._environmentProperties) : null;
             _forwardingLoggers = other._forwardingLoggers != null ? new List<ForwardingLoggerRecord>(other._forwardingLoggers) : null;
             _globalProperties = other._globalProperties != null ? new PropertyDictionary<ProjectPropertyInstance>(other._globalProperties) : null;
+            _propertiesFromCommandLine = other._propertiesFromCommandLine != null ? new HashSet<string>(other._propertiesFromCommandLine) : null;
             HostServices = other.HostServices;
             _loggers = other._loggers != null ? new List<ILogger>(other._loggers) : null;
             _maxNodeCount = other._maxNodeCount;
@@ -472,6 +479,11 @@ public IDictionary<string, string> GlobalProperties
             }
         }
 
+        /// <summary>
+        /// Properties passed from the command line (e.g. by using /p:).
+        /// </summary>
+        public HashSet<string> PropertiesFromCommandLine => _propertiesFromCommandLine;
+
         /// <summary>
         /// Interface allowing the host to provide additional control over the build process.
         /// </summary>

src/Build/BackEnd/Components/RequestBuilder/IntrinsicTask.cs

@@ -6,6 +6,7 @@
 using System.Reflection;
 using Microsoft.Build.BackEnd.Logging;
 using Microsoft.Build.Execution;
+using Microsoft.Build.Framework;
 using Microsoft.Build.Shared;
 
 #nullable disable

src/Build/BackEnd/Components/RequestBuilder/IntrinsicTasks/PropertyGroupIntrinsicTask.cs

@@ -25,6 +25,8 @@ internal class PropertyGroupIntrinsicTask : IntrinsicTask
         /// </summary>
         private ProjectPropertyGroupTaskInstance _taskInstance;
 
+        private readonly PropertyTrackingSetting _propertyTrackingSettings;
+
         /// <summary>
         /// Create a new PropertyGroup task.
         /// </summary>
@@ -36,6 +38,7 @@ public PropertyGroupIntrinsicTask(ProjectPropertyGroupTaskInstance taskInstance,
             : base(loggingContext, projectInstance, logTaskInputs)
         {
             _taskInstance = taskInstance;
+            _propertyTrackingSettings = (PropertyTrackingSetting)Traits.Instance.LogPropertyTracking;
         }
 
         /// <summary>
@@ -85,6 +88,8 @@ internal override void ExecuteTask(Lookup lookup)
                             string evaluatedValue = bucket.Expander.ExpandIntoStringLeaveEscaped(property.Value, ExpanderOptions.ExpandAll, property.Location);
                             bucket.Expander.PropertiesUseTracker.CheckPreexistingUndefinedUsage(property, evaluatedValue, LoggingContext);
 
+                            PropertyTrackingUtils.LogPropertyAssignment(_propertyTrackingSettings, property.Name, evaluatedValue, property.Location, Project.GetProperty(property.Name)?.EvaluatedValue ?? null, LoggingContext);
+
                             if (LogTaskInputs && !LoggingContext.LoggingService.OnlyLogCriticalEvents)
                             {
                                 LoggingContext.LogComment(MessageImportance.Low, "PropertyGroupLogMessage", property.Name, evaluatedValue);

src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs

@@ -156,6 +156,8 @@ internal class TaskExecutionHost : IDisposable
         /// </summary>
         private readonly Dictionary<string, TaskFactoryWrapper> _intrinsicTasks = new Dictionary<string, TaskFactoryWrapper>(StringComparer.OrdinalIgnoreCase);
 
+        private readonly PropertyTrackingSetting _propertyTrackingSettings;
+
         /// <summary>
         /// Constructor
         /// </summary>
@@ -172,6 +174,8 @@ internal TaskExecutionHost(IBuildComponentHost host)
             {
                 LogTaskInputs = Traits.Instance.EscapeHatches.LogTaskInputs;
             }
+
+            _propertyTrackingSettings = (PropertyTrackingSetting)Traits.Instance.LogPropertyTracking;
         }
 
         /// <summary>
@@ -1582,12 +1586,60 @@ private void GatherArrayStringAndValueOutputs(bool outputTargetIsItem, string ou
                             }
                         }
 
+                        PropertyTrackingUtils.LogPropertyAssignment(_propertyTrackingSettings, outputTargetName, outputString, parameterLocation, _projectInstance.GetProperty(outputTargetName)?.EvaluatedValue ?? null, _targetLoggingContext);
+
                         _batchBucket.Lookup.SetProperty(ProjectPropertyInstance.Create(outputTargetName, outputString, parameterLocation, _projectInstance.IsImmutable));
                     }
                 }
             }
         }
 
+        /// <summary>
+        /// Logs property assignment information during task execution, based on configured property tracking settings.
+        /// </summary>
+        /// <param name="propertyName">The name of the property being assigned or reassigned.</param>
+        /// <param name="propertyValue">The new value being assigned to the property.</param>
+        /// <param name="location">The source location where the property assignment occurs.</param>
+        private void LogPropertyInTaskAssignment(string propertyName, string propertyValue, IElementLocation location)
+        {
+            if (_propertyTrackingSettings == PropertyTrackingSetting.None)
+            {
+                return;
+            }
+
+            var previousPropertyValue = _projectInstance.GetProperty(propertyName)?.EvaluatedValue;
+
+            if (previousPropertyValue == null && PropertyTrackingUtils.IsPropertyTrackingEnabled(_propertyTrackingSettings, PropertyTrackingSetting.PropertyInitialValueSet))
+            {
+                var args = new PropertyInitialValueSetEventArgs(
+                    propertyName,
+                    propertyValue,
+                    propertySource: string.Empty,
+                    location.File,
+                    location.Line,
+                    location.Column,
+                    message: null)
+                { BuildEventContext = _targetLoggingContext.BuildEventContext };
+
+                _targetLoggingContext.LogBuildEvent(args);
+            }
+            else if (PropertyTrackingUtils.IsPropertyTrackingEnabled(_propertyTrackingSettings, PropertyTrackingSetting.PropertyReassignment))
+            {
+                var args = new PropertyReassignmentEventArgs(
+                    propertyName,
+                    previousPropertyValue,
+                    propertyValue,
+                    location: null,
+                    location.File,
+                    location.Line,
+                    location.Column,
+                    message: null)
+                { BuildEventContext = _targetLoggingContext.BuildEventContext };
+
+                _targetLoggingContext.LogBuildEvent(args);
+            }
+        }
+
         /// <summary>
         /// Finds all the task properties that are required.
         /// Returns them as keys in a dictionary.

src/Build/Definition/Project.cs

@@ -3721,6 +3721,7 @@ private void Reevaluate(
                     loadSettings,
                     ProjectCollection.MaxNodeCount,
                     ProjectCollection.EnvironmentProperties,
+                    ProjectCollection.PropertiesFromCommandLine,
                     loggingServiceForEvaluation,
                     new ProjectItemFactory(Owner),
                     ProjectCollection,
@@ -4437,7 +4438,7 @@ public IItemDefinition<ProjectMetadata> GetItemDefinition(string itemType)
             /// <summary>
             /// Sets a property which is not derived from Xml.
             /// </summary>
-            public ProjectProperty SetProperty(string name, string evaluatedValueEscaped, bool isGlobalProperty, bool mayBeReserved, LoggingContext loggingContext, bool isEnvironmentVariable = false)
+            public ProjectProperty SetProperty(string name, string evaluatedValueEscaped, bool isGlobalProperty, bool mayBeReserved, LoggingContext loggingContext, bool isEnvironmentVariable = false, bool isCommandLineProperty = false)
             {
                 ProjectProperty property = ProjectProperty.Create(Project, name, evaluatedValueEscaped, isGlobalProperty, mayBeReserved, loggingContext);
                 Properties.Set(property);

src/Build/Definition/ProjectCollection.cs

@@ -341,6 +341,9 @@ public ProjectCollection(IDictionary<string, string> globalProperties, IEnumerab
                 {
                     _globalProperties = new PropertyDictionary<ProjectPropertyInstance>(globalProperties.Count);
 
+                    // at this stage globalProperties collection contains entries passed from command line (e.g. /p:foo=bar).
+                    PropertiesFromCommandLine = [.. globalProperties.Keys];
+
                     foreach (KeyValuePair<string, string> pair in globalProperties)
                     {
                         try
@@ -497,6 +500,11 @@ public static string DisplayVersion
             }
         }
 
+        /// <summary>
+        /// Properties passed from the command line (e.g. by using /p:).
+        /// </summary>
+        public HashSet<string> PropertiesFromCommandLine { get; }
+
         /// <summary>
         /// The default tools version of this project collection. Projects use this tools version if they
         /// aren't otherwise told what tools version to use.