Users/haiz/add verbosity for target circular dependence

src/Build.UnitTests/BackEnd/TargetBuilder_Tests.cs

@@ -1254,6 +1254,35 @@ public void TestCircularDependencyInCallTarget()
             Assert.False(success);
         }
 
+        /// <summary>
+        /// Tests a circular dependency target.
+        /// </summary>
+        [Fact]
+        public void TestCircularDependencyTarget()
+        {
+            string projectContents = @"
+<Project xmlns=""http://schemas.microsoft.com/developer/msbuild/2003"">
+    <Target Name=""TargetA"" AfterTargets=""Build"" DependsOnTargets=""TargetB"">
+        <Message Text=""TargetA""></Message>
+    </Target>
+    <Target Name=""TargetB"" DependsOnTargets=""TargetC"">
+        <Message Text=""TargetB""></Message>
+    </Target>
+    <Target Name=""TargetC"" DependsOnTargets=""TargetA"">
+        <Message Text=""TargetC""></Message>
+    </Target>
+</Project>
+      ";
+            string errorMessage = @"There is a circular dependency in the target dependency graph involving target ""TargetA"". Since ""TargetC"" has ""DependsOn"" dependence on ""TargetA"", the circular is TargetA<-TargetC<-TargetB<-TargetA.";
+
+            StringReader reader = new StringReader(projectContents);
+            Project project = new Project(new XmlTextReader(reader), null, null);
+            bool success = project.Build(_mockLogger);
+            Assert.False(success);
+            Assert.Equal<int>(1, _mockLogger.ErrorCount);
+            Assert.Equal(errorMessage, _mockLogger.Errors[0].Message);
+        }
+
         /// <summary>
         /// Tests that cancel with no entries after building does not fail.
         /// </summary>

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

@@ -677,7 +677,7 @@ private async Task<bool> PushTargets(IList<TargetSpecification> targets, TargetE
                         // continue so we could throw the exception.
                         if (_requestEntry.RequestConfiguration.ActivelyBuildingTargets.ContainsKey(targetSpecification.TargetName))
                         {
-                            ProjectErrorUtilities.ThrowInvalidProject(targetLocation, "CircularDependency", targetSpecification.TargetName);
+                            ProjectErrorUtilities.ThrowInvalidProject(targetLocation, "CircularDependencyInTargetGraph", targetSpecification.TargetName, null);
                         }
                     }
                     else
@@ -689,7 +689,7 @@ private async Task<bool> PushTargets(IList<TargetSpecification> targets, TargetE
                         }
 
                         // We are already building this target on this request. That's a circular dependency.
-                        ProjectErrorUtilities.ThrowInvalidProject(targetLocation, "CircularDependency", targetSpecification.TargetName);
+                        ProjectErrorUtilities.ThrowInvalidProject(targetLocation, "CircularDependencyInTargetGraph", targetSpecification.TargetName, null);
                     }
                 }
                 else
@@ -698,12 +698,15 @@ private async Task<bool> PushTargets(IList<TargetSpecification> targets, TargetE
                     if (buildReason == TargetBuiltReason.BeforeTargets || buildReason == TargetBuiltReason.DependsOn || buildReason == TargetBuiltReason.None)
                     {
                         TargetEntry currentParent = parentTargetEntry;
+                        List<string> parentChain = new List<string>() { targetSpecification.TargetName };
                         while (currentParent != null)
                         {
+                            parentChain.Add(currentParent.Name);
                             if (String.Equals(currentParent.Name, targetSpecification.TargetName, StringComparison.OrdinalIgnoreCase))
                             {
                                 // We are already building this target on this request. That's a circular dependency.
-                                ProjectErrorUtilities.ThrowInvalidProject(targetLocation, "CircularDependency", targetSpecification.TargetName);
+                                string errorMessage = $"Since \"{parentTargetEntry.Name}\" has \"{buildReason}\" dependence on \"{targetSpecification.TargetName}\", the circular is {string.Join("<-", parentChain)}.";
+                                ProjectErrorUtilities.ThrowInvalidProject(targetLocation, "CircularDependencyInTargetGraph", targetSpecification.TargetName, errorMessage);
                             }
 
                             currentParent = currentParent.ParentEntry;

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

@@ -866,7 +866,7 @@ private async Task<WorkUnitResult> ExecuteInstantiatedTask(ITaskExecutionHost ta
                     else if (type == typeof(CircularDependencyException))
                     {
                         _continueOnError = ContinueOnError.ErrorAndStop;
-                        ProjectErrorUtilities.ThrowInvalidProject(taskLoggingContext.Task.Location, "CircularDependency", taskLoggingContext.TargetLoggingContext.Target.Name);
+                        ProjectErrorUtilities.ThrowInvalidProject(taskLoggingContext.Task.Location, "CircularDependencyInTargetGraph", taskLoggingContext.TargetLoggingContext.Target.Name);
                     }
                     else if (type == typeof(InvalidProjectFileException))
                     {

src/Build/Resources/Strings.resx

@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
 <root>
-  <!-- 
-    Microsoft ResX Schema 
-    
+  <!--
+    Microsoft ResX Schema
+
     Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
+
+    The primary goals of this format is to allow a simple XML format
+    that is mostly human readable. The generation and parsing of the
+    various data types are done through the TypeConverter classes
     associated with the data types.
-    
+
     Example:
-    
+
     ... ado.net/XML headers & schema ...
     <resheader name="resmimetype">text/microsoft-resx</resheader>
     <resheader name="version">2.0</resheader>
@@ -26,36 +26,36 @@
         <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
         <comment>This is a comment</comment>
     </data>
-                
-    There are any number of "resheader" rows that contain simple 
+
+    There are any number of "resheader" rows that contain simple
     name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
+
+    Each data row contains a name, and value. The row also contains a
+    type or mimetype. Type corresponds to a .NET class that support
+    text/value conversion through the TypeConverter architecture.
+    Classes that don't support this are serialized and stored with the
     mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
+
+    The mimetype is used for serialized objects, and tells the
+    ResXResourceReader how to depersist the object. This is currently not
     extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
+
+    Note - application/x-microsoft.net.object.binary.base64 is the format
+    that the ResXResourceWriter will generate, however the reader can
     read any of the formats listed below.
-    
+
     mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
             : and then encoded with base64 encoding.
-    
+
     mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
             : and then encoded with base64 encoding.
 
     mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
+    value   : The object must be serialized into a byte array
             : using a System.ComponentModel.TypeConverter
             : and then encoded with base64 encoding.
     -->
@@ -264,8 +264,8 @@
     <comment>{StrBegin="MSB4114: "}UE: This message appears if the project file contains unreasonably nested Choose elements.
     LOCALIZATION: Do not localize "Choose" as it is an XML element name.</comment>
   </data>
-  <data name="CircularDependency" xml:space="preserve">
-    <value>MSB4006: There is a circular dependency in the target dependency graph involving target "{0}".</value>
+  <data name="CircularDependencyInTargetGraph" xml:space="preserve">
+    <value>MSB4006: There is a circular dependency in the target dependency graph involving target "{0}". {1}</value>
     <comment>{StrBegin="MSB4006: "}UE: This message is shown when the build engine detects a target referenced in a circular manner -- a project cannot
     request a target to build itself (perhaps via a chain of other targets).</comment>
   </data>