Improve the message when UsingTask Reference Include is empty

src/Tasks.UnitTests/CodeTaskFactoryTests.cs

@@ -283,30 +283,34 @@ public void EmptySource()
         /// <summary>
         /// Verify we get an error if a reference is missing an include attribute is set but it is empty
         /// </summary>
-        [Fact]
-        public void EmptyReferenceInclude()
+        [Theory]
+        [InlineData("")]
+        [InlineData("Include=\"\"")]
+        [InlineData("Include=\" \"")]
+        public void EmptyReferenceInclude(string includeSetting)
         {
-            string projectFileContents = @"
+            string taskName = "CustomTaskFromCodeFactory_EmptyReferenceInclude";
+            string projectFileContents = @$"
                     <Project ToolsVersion='msbuilddefaulttoolsversion'>
-                        <UsingTask TaskName=`CustomTaskFromCodeFactory_EmptyReferenceInclude` TaskFactory=`CodeTaskFactory` AssemblyFile=`$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll` >
+                        <UsingTask TaskName=`{taskName}` TaskFactory=`CodeTaskFactory` AssemblyFile=`$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll` >
                          <ParameterGroup>
                              <Text/>
                           </ParameterGroup>
                             <Task>
-                                 <Reference/>
+                                 <Reference {includeSetting}/>
                                 <Code>
                                        Log.LogMessage(MessageImportance.High, Text);
                                 </Code>
                             </Task>
                         </UsingTask>
                         <Target Name=`Build`>
-                            <CustomTaskFromCodeFactory_EmptyReferenceInclude/>
+                            <{taskName}/>
                         </Target>
                     </Project>";
 
             MockLogger mockLogger = Helpers.BuildProjectWithNewOMExpectFailure(projectFileContents, false);
-            string unformattedMessage = ResourceUtilities.GetResourceString("CodeTaskFactory.AttributeEmpty");
-            mockLogger.AssertLogContains(String.Format(unformattedMessage, "Include"));
+            string unformattedMessage = ResourceUtilities.GetResourceString("CodeTaskFactory.AttributeEmptyWithTaskElement");
+            mockLogger.AssertLogContains(String.Format(unformattedMessage, "Include", "Reference", taskName));
         }
 
         /// <summary>

src/Tasks.UnitTests/RoslynCodeTaskFactory_Tests.cs

@@ -438,12 +438,15 @@ public void EmptyCodeElement()
                 expectedErrorMessage: "You must specify source code within the Code element or a path to a file containing source code.");
         }
 
-        [Fact]
-        public void EmptyIncludeAttributeOnReferenceElement()
+        [Theory]
+        [InlineData("")]
+        [InlineData("Include=\"\"")]
+        [InlineData("Include=\" \"")]
+        public void EmptyIncludeAttributeOnReferenceElement(string includeSetting)
         {
             TryLoadTaskBodyAndExpectFailure(
-                taskBody: "<Reference Include=\"\" />",
-                expectedErrorMessage: "The \"Include\" attribute of the <Reference> element has been set but is empty. If the \"Include\" attribute is set it must not be empty.");
+                taskBody: $"<Reference {includeSetting} />",
+                expectedErrorMessage: $"The \"Include\" attribute of the <Reference> element in the task \"{TaskName}\" has been set but is empty. Make sure the attribute has a proper value.");
         }
 
         [Fact]

src/Tasks/CodeTaskFactory.cs

@@ -436,9 +436,9 @@ private List<string> ExtractReferencedAssemblies()
                     return null;
                 }
 
-                if (attribute == null || attribute.Value.Length == 0)
+                if (string.IsNullOrWhiteSpace(attribute?.Value))
                 {
-                    _log.LogErrorWithCodeFromResources("CodeTaskFactory.AttributeEmpty", "Include");
+                    _log.LogErrorWithCodeFromResources("CodeTaskFactory.AttributeEmptyWithTaskElement", "Include", "Reference", _nameOfTask);
                     return null;
                 }
 

src/Tasks/Resources/Strings.resx

@@ -2480,6 +2480,10 @@
     <value>MSB3752: The "{0}" attribute of the &lt;{1}&gt; element has been set but is empty. If the "{0}" attribute is set it must not be empty.</value>
     <comment>{StrBegin="MSB3752: "}</comment>
   </data>
+  <data name="CodeTaskFactory.AttributeEmptyWithTaskElement" xml:space="preserve">
+    <value>MSB3752: The "{0}" attribute of the &lt;{1}&gt; element in the task "{2}" has been set but is empty. Make sure the attribute has a proper value.</value>
+    <comment>{StrBegin="MSB3752: "}</comment>
+  </data>
   <data name="CodeTaskFactory.NeedsITaskInterface" xml:space="preserve">
     <value>MSB3753: The task could not be instantiated because it does not implement the ITask interface. Make sure the task implements the Microsoft.Build.Framework.ITask interface.</value>
     <comment>{StrBegin="MSB3753: "}</comment>