Link that can reference multiple content types is not being mapped

[georgezubov]

Affected version: 8.3.0 and 8.2.1

Issue:

Hello, we have following content type structure:

public class Type1
{
    public IContentType[] Items { get; set; }
}

public class Type2: IContentType
{
    public Type3[] Items { get; set; }
}

public class Type3
{
    public IContentType Field { get; set; }
}

public interface IContentType {}

When we put object of Type2 in the items of Type1, Field of Type3 (which can be the reference to a multiple content types) is always deserialized as null.

Workaround for us is rolling back to version 7.6.1, there everything works as expected.

Here is a redacted version of the API response - test.json

Could you please take a look and help us to resolve this issue? Let me know if any additional information is required. Thanks in advance!

[Roblinde]

georgezubov this seems to work fine for me. In the class you deserialize into, are you using dynamic of JObject as any of the property types?

[georgezubov]

Robert Linde (@Roblinde) no, we don't use dynamic of JObject in our models. Maybe it could also be important - there is actually one more layer above the Type1:

public class Type0
{
    public IContentType[] Items { get; set; }
}

So the object of Type1 is added to the Items of Type0.

[Roblinde]

georgezubov interesting, could you share all your classes and I'll try to figure out what's going on. (Just need the relevant properties)

[georgezubov]

Robert Linde (@Roblinde) , here are redacted relevant classes and interfaces (without non-related properties) -
Test1.zip. Thanks a lot for looking into it!

[Roblinde]

georgezubov do you have a contenttype resolver configured as well? To map your IContentModel interface?

[Roblinde]

When I set the classes up like this (some minor changes from your example) I get everything resolved just fine:

public class Level1ContentModel : ContentModelWithId
{
    // an entry of Level2ContentModel is added here
    public IList<Level2ContentModel> Items { get; set; } = new List<Level2ContentModel>();
}

public class Level2ContentModel : ContentModelWithId
{
    //[JsonProperty("DifferentFieldNameInCF")]
    public IList<Level3ContentModel> Items { get; } = new List<Level3ContentModel>();
}

public sealed class Level3ContentModel : ContentModelWithId, IContent
{
    // Here we're always getting null after deserialization. We expect an instanse of Level4ContentModel
    public Level4ContentModel TargetField { get; set; }
}

public class Level4ContentModel : BaseContentModel, IContent
{
    public string Field1 { get; set; }
}

[georgezubov]

Robert Linde (@Roblinde) yes, we have an implementation of IContentTypeResolver which maps specific content types using custom attribute with the content type ID.

[Roblinde]

georgezubov ok, I'll set up a simple content type resolver as well and see if I can reproduce the problem.

[Roblinde]

georgezubov it works fine with a contenttype resolver as well... hmm, is there anything else that could be pertinent?

My simple resolver just looked like this:

public class LevelsContentTypeResolver : IContentTypeResolver
{
    public Type Resolve(string contentTypeId)
    {
        if(contentTypeId == "<TYPE1>")
        {
            return typeof(Level1ContentModel);
        }
        if (contentTypeId == "<TYPE2>")
        {
            return typeof(Level2ContentModel);
        }
        if (contentTypeId == "TYPE3")
        {
            return typeof(Level3ContentModel);
        }
        if (contentTypeId == "TYPE4")
        {
            return typeof(Level4ContentModel);
        }

        return null;
    }
}

[georgezubov]

Robert Linde (@Roblinde) actual serialization error looks like following:

JsonSerializationException: Could not create an instance of type IContentModel. Type is an interface or abstract class and cannot be instantiated. Path 'items[0].items[0].listOfItems[0].targetField.sys', line , position .

If I change a type of target field to specific type (Level4ContentModel), the instance of the class will be created, but all properties inside of it are null (except SystemProperties, which has Id, LinkType and Type fields populated).

[Roblinde]

Aaah, so it's a serialization issue. Is your Level4ContentModel missing from your contenttype resolver by any chance?

[georgezubov]

Robert Linde (@Roblinde) nope, it is being deserialized correctly when it is referenced anywhere else (e.g. in Level1ContentModel). And also everything works as expected in version 7.7.0.

[Roblinde]

hmm, that is certainly weird. Version 7.7.0 introduced a faulty way of doing serialization that broke when an item was referenced multiple times so we can't go back to that anyway.

It's weird that it's pointing to targetField.sys

In your actual live example, is your Level4 entry present anywhere else in the structure or is it exactly as the test.json you provided me?

[georgezubov]

Robert Linde (@Roblinde) You're right, I'm sorry for the misleading, we have rolled back to the 7.6.1, not to the 7.7.0

In your actual live example, is your Level4 entry present anywhere else in the structure or is it exactly as the test.json you provided me?

In the very first response where we spotted the problem, this Level4 was referenced by 2 different entries in the structure, but after that I created separate set of entries and Level4 entry was referenced only once, the result is the same. For both cases, the entry itself is present only in includes. I can try to provide the whole redacted response if that would help.

[Roblinde]

If you could that would be great, I'm running out of ideas, but somehow I must be able to reproduce this and find the bug.