Sort failing due to serialization error

[curtismbeard]

When I apply a sort, the response is throwing an error when trying to convert the hits back to concrete types.

After looking into the code, it appears that the _score is null when a sort is applied. However, it fails to convert and throws an error. If I set TrackScores to true, it works correctly (_score comes back as 0 in this case). This happens on line 125 in https://github.com/elastic/elasticsearch-net/blob/master/src/Nest/CommonAbstractions/SerializationBehavior/StatefulDeserialization/ConcreteTypeConverter.cs

Here is the exception:
Microsoft.CSharp.RuntimeBinder.RuntimeBinderException was unhandled by user code
HResult=-2146233088
Message=Cannot implicitly convert type 'Newtonsoft.Json.Linq.JValue' to 'double'. An explicit conversion exists (are you missing a cast?)
Source=Anonymously Hosted DynamicMethods Assembly
StackTrace:
at CallSite.Target(Closure , CallSite , Object )
at Nest.ConcreteTypeConverter.GetConcreteTypeUsingSelector[T](JsonSerializer serializer, ConcreteTypeConverter1 realConcreteConverter, JObject jObject) in c:\code\elasticsearch-net\src\Nest\CommonAbstractions\SerializationBehavior\StatefulDeserialization\ConcreteTypeConverter.cs:line 125 at Nest.ConcreteTypeConverter.GetUsingConcreteTypeConverter[T](JsonReader reader, JsonSerializer serializer, ConcreteTypeConverter1 realConcreteConverter) in c:\code\elasticsearch-net\src\Nest\CommonAbstractions\SerializationBehavior\StatefulDeserialization\ConcreteTypeConverter.cs:line 83
at Nest.ConcreteTypeConverter`1.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) in c:\code\elasticsearch-net\src\Nest\CommonAbstractions\SerializationBehavior\StatefulDeserialization\ConcreteTypeConverter.cs:line 62
at Nest.DefaultHitJsonConverter.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) in c:\code\elasticsearch-net\src\Nest\CommonAbstractions\SerializationBehavior\StatefulDeserialization\ConcreteTypeConverter.cs:line 24
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, Object existingValue)
at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateList(IList list, JsonReader reader, JsonArrayContract contract, JsonProperty containerProperty, String id)
InnerException:

[russcam]

@curtismbeard What version of NEST are you using, 2.x?

Do you have a minimum reproducible example that I can have a look at this with?

[RTroywest]

This should reproduce the error I think.
`

public interface IThing
{
    int Int { get; set; }
    string String { get; set; }
}   

class ThingA : IThing
{
    public int Int { get; set; }
    public string String { get; set; }
    public string A { get; set; }
}

class ThingB : IThing
{
    public int Int { get; set; }
    public string String { get; set; }
    public string B { get; set; }
}
class ThingC : IThing
{
    public int Int { get; set; }
    public string String { get; set; }
    public string C { get; set; }
}

class Program
{
    static void Main(string[] args)
    {
       var client = new ElasticClient(settings);

        if (!client.IndexExists(new IndexExistsRequest("multitype")).Exists)
        {
            client.CreateIndex("multitype");
            var response = client.Map<ThingA>(m => m.Index("multitype").AutoMap());
            if (!response.IsValid)
            {
                throw new Exception(response.DebugInformation);
            }
            response = client.Map<ThingB>(m => m.Index("multitype").AutoMap());
            if (!response.IsValid)
            {
                throw new Exception(response.DebugInformation);
            }
            response = client.Map<ThingC>(m => m.Index("multitype").AutoMap());
            if (!response.IsValid)
            {
                throw new Exception(response.DebugInformation);
            }
        }

        client.Index(new ThingA {A = "Somthing for A", Int = 1, String = "thinga"});
        client.Index(new ThingA {A = "Somthing for A", Int = 2, String = "thinga"});
        client.Index(new ThingB {B = "Somthing for B", Int = 3, String = "thingb"});

        var searchResponse = client.Search<IThing>(
            s =>
                s.Index<ThingA>()//search correct index
                    .Type("thinga,thingb,thingc")
                    .ConcreteTypeSelector((v, y) =>
                    {
                        switch (y.Type)
                        {
                            case "thinga":
                                return typeof (ThingA);
                            case "thingb":
                                return typeof (ThingB);
                            case "thingc":
                                return typeof (ThingC);
                            default:
                                throw new Exception(y.Type);
                        }
                    })
                    .Query(x => x.Term(trm => trm.String, "thingb"))
                    .Sort(srt => srt.Ascending(fld => fld.Int))
                    .Skip(0)
                    .Take(10));}}`

[curtismbeard]

I will work on a simple example that reproduces the issue. I am using 2.0.2.

[tbrooks007]

I ran into this issue last night. I am using v2.0.2 as well. I was sorting on both the _score field and a mapped date field. When sorting by the score only, I didn't receive the error but when I tried to sort on both the score and the date fields I received the same error listed in this ticket. In NEST 1.4 this worked. After doing some more reading on sorting, I see that scores will not be returned if you are sorting on a field unless you set TrackScores to true. This will ensure that the that scores will be tracked and computed. After I add this to my query, the query returned mixed type results using both _score and the mapped date field. All serialization worked as well.

Hope this helps.

[gmarz]

Thank you all for reporting this. It'll be fixed in the next release.