-Improved error when attempting to convert root JSON object property to an XML attribute

Src/Newtonsoft.Json.Tests/Converters/XmlNodeConverterTest.cs

@@ -2701,6 +2701,35 @@ namespace Newtonsoft.Json.Tests.Converters
             Assert.AreEqual(json, json2);
         }
 
+        [Test]
+        public void RootPropertyError()
+        {
+            string json = @"{
+  ""$id"": ""1"",
+  ""AOSLocaleName"": ""en-US"",
+  ""AXLanguage"": ""EN-AU"",
+  ""Company"": ""AURE"",
+  ""CompanyTimeZone"": 8,
+  ""CurrencyInfo"": {
+    ""$id"": ""2"",
+    ""CurrencyCode"": ""AUD"",
+    ""Description"": ""Australian Dollar"",
+    ""ExchangeRate"": 100.0,
+    ""ISOCurrencyCode"": ""AUD"",
+    ""Prefix"": """",
+    ""Suffix"": """"
+  },
+  ""IsSysAdmin"": true,
+  ""UserId"": ""lamar.miller"",
+  ""UserPreferredCalendar"": 0,
+  ""UserPreferredTimeZone"": 8
+}";
+
+            ExceptionAssert.Throws<JsonSerializationException>(
+                () => JsonConvert.DeserializeXmlNode(json),
+                "JSON root object has property '$id' that will be converted to an attribute. A root object cannot have any attribute properties. Consider specifing a DeserializeRootElementName. Path '$id', line 2, position 12.");
+        }
+
         [Test]
         public void SerializeEmptyNodeAndOmitRoot()
         {

Src/Newtonsoft.Json/Converters/XmlNodeConverter.cs

@@ -1538,7 +1538,7 @@ namespace Newtonsoft.Json.Converters
                 string attributeName = propertyName.Substring(1);
                 string attributePrefix = MiscellaneousUtils.GetPrefix(attributeName);
 
-                AddAttribute(reader, document, currentNode, attributeName, manager, attributePrefix);
+                AddAttribute(reader, document, currentNode, propertyName, attributeName, manager, attributePrefix);
                 return;
             }
 
@@ -1557,7 +1557,7 @@ namespace Newtonsoft.Json.Converters
                     case JsonTypeReflector.ValuePropertyName:
                         string attributeName = propertyName.Substring(1);
                         string attributePrefix = manager.LookupPrefix(JsonNamespaceUri);
-                        AddAttribute(reader, document, currentNode, attributeName, manager, attributePrefix);
+                        AddAttribute(reader, document, currentNode, propertyName, attributeName, manager, attributePrefix);
                         return;
                 }
             }
@@ -1614,8 +1614,13 @@ namespace Newtonsoft.Json.Converters
             }
         }
 
-        private static void AddAttribute(JsonReader reader, IXmlDocument document, IXmlNode currentNode, string attributeName, XmlNamespaceManager manager, string attributePrefix)
+        private static void AddAttribute(JsonReader reader, IXmlDocument document, IXmlNode currentNode, string propertyName, string attributeName, XmlNamespaceManager manager, string attributePrefix)
         {
+            if (currentNode.NodeType == XmlNodeType.Document)
+            {
+                throw JsonSerializationException.Create(reader, "JSON root object has property '{0}' that will be converted to an attribute. A root object cannot have any attribute properties. Consider specifing a DeserializeRootElementName.".FormatWith(CultureInfo.InvariantCulture, propertyName));
+            }
+
             string encodedName = XmlConvert.EncodeName(attributeName);
             string attributeValue = reader.Value.ToString();