JsonSourceGenerationOptionsAttribute should provide an option for enabling string enum serialization globally

[eiriktsarpalis]

• While we can register the convert globally, there is no good way to ensure all enums are registered

Originally posted by @terrajobst in #79311 (comment)

API Proposal

namespace System.Text.Json.Serialization;

public partial class JsonSourceGenerationOptionsAttribute
{
     public bool UseStringEnumConverter { get; set; } = false;
}

API Usage

JsonSerializer.Serialize(new MyPoco(), MyContext.Default.MyPoco); // {"Property1":"Public","Property2":"Static","Property3":"Instance"}

public class MyPoco
{
    public BindingFlags Property1 { get; set; } = BindingFlags.Public;
    public BindingFlags Property2 { get; set; } = BindingFlags.Static;
    public BindingFlags Property3 { get; set; } = BindingFlags.Instance;
}

[JsonSourceGenerationOptions(UseStringEnumConverter = true)]
[JsonSerializable(typeof(MyPoco))]
public partial class MyContext { }

Related to #81985 which tracks support for compile-time control of JsonSerializerDefaults.Web.

cc @halter73

[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

---

• While we can register the convert globally, there is no good way to ensure all enums are registered

Originally posted by @terrajobst in #79311 (comment)

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

[eiriktsarpalis]

Related to #57321.

[terrajobst]

Video

• Looks good as proposed
• We decided to add a converter that lets people serialize enums as numbers as a way to offset the global switch

namespace System.Text.Json.Serialization;

public partial class JsonSourceGenerationOptionsAttribute
{
     public bool UseStringEnumConverter { get; set; } = false;
}

public partial class JsonNumberEnumConverter<TEnum> : JsonConverterFactory
    where TEnum : struct, Enum
{
    public JsonNumberEnumConverter();

    public sealed override bool CanConvert(System.Type typeToConvert);
    public sealed override JsonConverter CreateConverter(Type typeToConvert, JsonSerializerOptions options);
}