Parse invalid property under target

documentation/wiki/ChangeWaves-Dev.md

@@ -51,7 +51,7 @@ Surround your feature with the following:
 
 If you need to condition a Task or Target, use the built in `AreFeaturesEnabled` function.
 ```xml
-<Target Name="SomeRiskyChange" Condition="$([MSBuild]::AreFeaturesEnabled('17.4'))"">
+<Target Name="SomeRiskyChange" Condition="$([MSBuild]::AreFeaturesEnabled('17.4'))">
 <!-- Where '17.4' is the change wave assigned to your feature. -->
 ```
 

documentation/wiki/ChangeWaves.md

@@ -24,6 +24,7 @@ A wave of features is set to "rotate out" (i.e. become standard functionality) t
 ## Current Rotation of Change Waves
 
 ### 17.6
+- [Parse invalid property under target](https://github.com/dotnet/msbuild/pull/8190)
 - [Eliminate project string cache](https://github.com/dotnet/msbuild/pull/7965)
 - [Log an error when no provided search path for an import exists](https://github.com/dotnet/msbuild/pull/8095)
 

src/Build.OM.UnitTests/Construction/ProjectTargetElement_Tests.cs

@@ -5,9 +5,13 @@
 using System.IO;
 using System.Xml;
 using Microsoft.Build.Construction;
+using Microsoft.Build.Evaluation;
+using Microsoft.Build.Framework;
+using Microsoft.Build.Shared;
+using Shouldly;
+using Xunit;
 
 using InvalidProjectFileException = Microsoft.Build.Exceptions.InvalidProjectFileException;
-using Xunit;
 
 #nullable disable
 
@@ -339,6 +343,51 @@ public void SetReturns()
             Assert.True(project.HasUnsavedChanges);
         }
 
+        /// <summary>
+        /// Parse invalid property under target
+        /// </summary>
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void ReadInvalidPropertyUnderTarget(bool enableNewBehavior)
+        {
+            using (TestEnvironment env = TestEnvironment.Create())
+            {
+                ChangeWaves.ResetStateForTests();
+
+                if (!enableNewBehavior)
+                {
+                    env.SetEnvironmentVariable("MSBUILDDISABLEFEATURESFROMVERSION", ChangeWaves.Wave17_6.ToString());
+                    BuildEnvironmentHelper.ResetInstance_ForUnitTestsOnly();
+                }
+
+                string projectFile = @"
+                    <Project>
+                        <Target Name='t'>
+                            <test>m</test>
+                        </Target>
+                    </Project>";
+
+                TransientTestFile file = env.CreateFile("proj.csproj", projectFile);
+                ProjectCollection collection = new ProjectCollection();
+                var error = Assert.Throws<InvalidProjectFileException>(() =>
+                {
+                    collection.LoadProject(file.Path).Build().ShouldBeTrue();
+                });
+
+                var expectedString = "If you intended this to be a property, it must be inside a <PropertyGroup> element";
+
+                if (ChangeWaves.AreFeaturesEnabled(ChangeWaves.Wave17_6))
+                {
+                    error.Message.ShouldMatch(expectedString);
+                }
+                else
+                {
+                    error.ErrorCode.ShouldNotMatch(expectedString);
+                }
+            }
+        }
+
         /// <summary>
         /// Helper to get an empty ProjectTargetElement with various attributes and two tasks
         /// </summary>

src/Build/Evaluation/ProjectParser.cs

@@ -6,6 +6,7 @@
 using Microsoft.Build.Shared;
 using System;
 using System.Collections.Generic;
+using System.Xml;
 
 using Expander = Microsoft.Build.Evaluation.Expander<Microsoft.Build.Evaluation.ProjectProperty, Microsoft.Build.Evaluation.ProjectItem>;
 using ProjectXmlUtilities = Microsoft.Build.Internal.ProjectXmlUtilities;
@@ -634,6 +635,14 @@ private ProjectTargetElement ParseProjectTargetElement(XmlElementWithLocation el
                         if (onError != null)
                         {
                             ProjectErrorUtilities.ThrowInvalidProject(onError.Location, "NodeMustBeLastUnderElement", XMakeElements.onError, XMakeElements.target, childElement.Name);
+                        }                       
+                        if (ChangeWaves.AreFeaturesEnabled(ChangeWaves.Wave17_6))
+                        {
+                            if (childElement.ChildNodes.Count == 1 && childElement.FirstChild.NodeType == XmlNodeType.Text)
+                            {
+                                // If the element has inner text and no other child elements except text, then this should be a property and throw invalid child element of <Target>
+                                ProjectErrorUtilities.ThrowInvalidProject(childElement.Location, "PropertyOutsidePropertyGroupInTarget", childElement.Name, childElement.ParentNode.Name);
+                            }
                         }
 
                         child = ParseProjectTaskElement(childElement, target);

src/Build/Resources/Strings.resx

@@ -1271,6 +1271,10 @@
     <value>MSB4067: The element &lt;{0}&gt; beneath element &lt;{1}&gt; is unrecognized.</value>
     <comment>{StrBegin="MSB4067: "}</comment>
   </data>
+  <data name="PropertyOutsidePropertyGroupInTarget" xml:space="preserve" Condition="$([MSBuild]::AreFeaturesEnabled('17.6'))">
+    <value>MSB4067: The element &lt;{0}&gt; beneath element &lt;{1}&gt; is unrecognized. If you intended this to be a property, it must be inside a &lt;PropertyGroup&gt; element.</value>
+    <comment>{StrBegin="MSB4067: "}</comment>
+  </data>
   <data name="InvalidChildElementDueToDuplication" xml:space="preserve">
     <value>MSB4173: The element &lt;{0}&gt; beneath element &lt;{1}&gt; is invalid because a child element with that name already exists</value>
     <comment>{StrBegin="MSB4173: "}</comment>