Fix enum deserialization when enum value contains underscores.

Author: Dusty Kline

src/ServiceStack.Text/Common/ParseUtils.cs

@@ -11,6 +11,7 @@
 //
 
 using System;
+using System.Linq;
 
 namespace ServiceStack.Text.Common
 {
@@ -64,7 +65,12 @@ public static Type ParseType(string assemblyQualifiedName)
         public static object TryParseEnum(Type enumType, string str)
         {
             if (JsConfig.EmitLowercaseUnderscoreNames)
-                str = str.Replace("_", "");
+            {
+                string[] names = Enum.GetNames(enumType);
+                if (!names.Contains(str))   // does this need StringComparer.InvariantCultureIgnoreCase?
+                    str = str.Replace("_", "");
+            }
+                
 
             return Enum.Parse(enumType, str, ignoreCase: true);
         }

tests/ServiceStack.Text.Tests/EnumTests.cs

@@ -149,10 +149,12 @@ public void Can_serialize_different_enum_styles()
         {
             Assert.That("Word".FromJson<EnumStyles>(), Is.EqualTo(EnumStyles.Word));
             Assert.That("DoubleWord".FromJson<EnumStyles>(), Is.EqualTo(EnumStyles.DoubleWord));
+            Assert.That("Underscore_Words".FromJson<EnumStyles>(), Is.EqualTo(EnumStyles.Underscore_Words));
 
             using (JsConfig.With(emitLowercaseUnderscoreNames: true))
             {
                 Assert.That("Double_Word".FromJson<EnumStyles>(), Is.EqualTo(EnumStyles.DoubleWord));
+                Assert.That("Underscore_Words".FromJson<EnumStyles>(), Is.EqualTo(EnumStyles.Underscore_Words));
             }
         }
     }