JsonConstructorAttribute not working for private/internal ctor in .NET 8.0 preview7

[TanvirArjel]

Description

Hello @eiriktsarpalis,

I have tested with .NET 8.0 Preview7 SDK with Rider. It's not working. It's throwing the following exception:

My SDKs:

Debug Log:

Employee class:

Reproduction Steps

Try in Rider with .NET 8.0 preview 7 SDK.

Expected behavior

It should have worked as mentioned here: #88452

Actual behavior

Not working. Throwing Unsupported exception.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

[eiriktsarpalis]

Hi @TanvirArjel, would it be possible to share your reproduction in text? It's difficult to transcribe using screenshots.

[ghost]

Tagging subscribers to this area: @dotnet/area-system-text-json, @gregsdennis
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

Hello @eiriktsarpalis,

I have tested with .NET 8.0 Preview7 SDK with Rider. It's not working. It's throwing the following exception:

My SDKs:

Debug Log:

Employee class:

Reproduction Steps

Try in Rider with .NET 8.0 preview 7 SDK.

Expected behavior

It should have worked as mentioned here: #88452

Actual behavior

Not working. Throwing Unsupported exception.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

Author:	TanvirArjel
Assignees:	-
Labels:	area-System.Text.Json, untriaged, needs-area-label
Milestone:	-

[huoyaoyuan]

The exception message says "parameterless constructor, a singular parameterized constructor or a parameterized constructor annotated with 'JsonConstructorAttribute'".

JsonConstructorAttribute is meant to be used on the constructor Employee(int id, string name).

[TanvirArjel]

@eiriktsarpalis Here it is:

The Program class:

using System;
using System.Text.Json;
using ConsoleApp2;

internal class Program
{
    public static void Main(string[] args)
    {
        Employee employee = new(1, "Tanvir");
        string jsonString = JsonSerializer.Serialize(employee);

        Employee deEmployee = JsonSerializer.Deserialize<Employee>(jsonString);
    }
}

The employee class:

public class Employee
{
    [JsonConstructor]
    private Employee()
    {
    }

    public Employee(int id, string name)
    {
        this.Id = id;
        this.Name = name;
    }
    
    public int Id { get; set; }

    public string Name { get; set; }
}

[TanvirArjel]

@huoyaoyuan For Employee(int id, string name) ctor, you don't even need JsonConstructorAttribute.

[huoyaoyuan]

For Employee(int id, string name) ctor, you don't even need JsonConstructorAttribute.

Right, sometimes it can't be determined and needs to be specified.
JsonConstructorAtttribute is used for a constructor accepting all properties, not parameterless constructor.

[TanvirArjel]

@huoyaoyuan Primary need of JsonConstructorAtttribute is to be used in private parameterless ctor. If it does not work then it is useless.

[eiriktsarpalis]

Appears to be a bug specific to applying the attribute to parameterless constructors. We should fix this.