Throw errors on blank strings or empty objects when checking for missing member handling

Source/destination types

 public class MyObj
 {
     public string Prop { get; set; }
 }

Source/destination JSON

(blank)
OR
{}

Expected behavior

An exception to be thrown

Actual behavior

Returned null value

Steps to reproduce

using Newtonsoft.Json;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var settings = new JsonSerializerSettings
            {
                MissingMemberHandling = MissingMemberHandling.Error
            };

            //unexpected
            JsonConvert.DeserializeObject<MyObj>("", settings); //returns null
            JsonConvert.DeserializeObject<MyObj>("{}", settings); //returns null

            //expected
            JsonConvert.DeserializeObject<MyObj>(null, settings); //throws System.ArgumentNullException
            JsonConvert.DeserializeObject<MyObj>("[]", settings); //throws Newtonsoft.Json.JsonSerializationException
            JsonConvert.DeserializeObject<MyObj>("{'Test': 'Test'}", settings); //throws Newtonsoft.Json.JsonSerializationException
            JsonConvert.DeserializeObject<MyObj>("{'Prop': 'Test'}", settings); //returns MyObj instance
        }
    }

    public class MyObj
    {
        public string Prop { get; set; }
    }
}

This is a minor issue I can code around, but it seemed like a bug.

[alex-valchuk]

I’m interested in throwing serialization exceptions in cases when a user provides json with a key (for a not required property) for which a relevant value=“” is supposed to be a complex object e.g:

// invalid json - exception should be thrown
{
    "user_info": ""
}

// valid json - no exceptions:
{
    "user_info": {
         "first_name": "John",
         "last_name": "Smith"
    }
}

Does anybody know how it can be achieved?

[vladd]

@alex-valchuk Your example can be further simplified to deserializing "" (i. e, an text containing a string) into an instance of UserInfo class. JsonConvert.DeserializeObject<UserInfo>("\"\"") returns null instead of throwing an exception. I believe this to be a bug.