Serialization of abstract properties

[zryska]

Description

Serialization behavior changed from System.Text.Json version 5.0.0 forward where overridden properties defined with JsonPropertyName decoration are both included in the resulting JSON payload (Id as well as OverridenId for example). We have seen performance degradation when upgrading to .NET 6 and after some investigation identified that the new serialization behavior is the root cause.

Object serialized with System.Text.Json version 4.7.2:

{"CarId":"ecfb9972-4cb9-41be-bbcc-2cfa1539314a","Name":"name","Description":"description"}

The same object serialized with System.Text.Json version 5.0.0

{"CarId":"9c77798e-402f-455b-abc6-49bd4dfa8d26","Id":"9c77798e-402f-455b-abc6-49bd4dfa8d26","Name":"name","Description":"description"}

Reproduction Steps

Define simple base class:

public abstract class ItemBase
{
    public abstract string Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
}

Define specific class and inherit the base class and change property name

public class Car : ItemBase
{
    [JsonPropertyName("CarId")]
    public override string Id { get; set; }
}

Run the example with System.Text.Json version 4.7.2 and upgrade to 5.0.0 or higher afterwards to see different result

static void Main(string[] args)
{
    var car = new Car
    {
        Id = Guid.NewGuid().ToString(),
        Name = "name",
        Description = "description",
    };

    var serializedBytes = JsonSerializer.SerializeToUtf8Bytes(car);

    Console.WriteLine(Encoding.UTF8.GetString(serializedBytes));
}

Repository with repro project: https://github.com/zryska/serialization-repro

Expected behavior

I would expect the behavior to be the same as for 4.7.2 version of System.Text.Json package - only overridden property is included in the payload.

Actual behavior

Both properties are included in the payload.

Regression?

No response

Known Workarounds

This can be mitigated by including [JsonIgnore] attribute on the base class property that shouldn't be included in the payload.

public abstract class ItemBase
{
    [JsonIgnore]
    public abstract string Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
}

Configuration

No response

Other information

No response

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Issue Details

---

Description

Serialization behavior changed from System.Text.Json version 5.0.0 forward where overridden properties defined with JsonPropertyName decoration are both included in the resulting JSON payload (Id as well as OverridenId for example). We have seen performance degradation when upgrading to .NET 6 and after some investigation identified that the new serialization behavior is the root cause.

Object serialized with System.Text.Json version 4.7.2:

{"CarId":"ecfb9972-4cb9-41be-bbcc-2cfa1539314a","Name":"name","Description":"description"}

The same object serialized with System.Text.Json version 5.0.0

{"CarId":"9c77798e-402f-455b-abc6-49bd4dfa8d26","Id":"9c77798e-402f-455b-abc6-49bd4dfa8d26","Name":"name","Description":"description"}

Reproduction Steps

Define simple base class:

public abstract class ItemBase
{
    public abstract string Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
}

Define specific class and inherit the base class and change property name

public class Car : ItemBase
{
    [JsonPropertyName("CarId")]
    public override string Id { get; set; }
}

Run the example with System.Text.Json version 4.7.2 and upgrade to 5.0.0 or higher afterwards to see different result

static void Main(string[] args)
{
    var car = new Car
    {
        Id = Guid.NewGuid().ToString(),
        Name = "name",
        Description = "description",
    };

    var serializedBytes = JsonSerializer.SerializeToUtf8Bytes(car);

    Console.WriteLine(Encoding.UTF8.GetString(serializedBytes));
}

Expected behavior

I would expect the behavior to be the same as for 4.7.2 version of System.Text.Json package - only overridden property is included in the payload.

Actual behavior

Both properties are included in the payload.

Regression?

No response

Known Workarounds

This can be mitigated by including [JsonIgnore] attribute on the base class property that shouldn't be included in the payload.

public abstract class ItemBase
{
    [JsonIgnore]
    public abstract string Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
}

Configuration

No response

Other information

No response

Author:	zryska
Assignees:	-
Labels:	area-System.Text.Json, untriaged
Milestone:	-

[eiriktsarpalis]

Duplicate of #51165.