Minimal API: JsonStringEnumMemberName doesn't work while deserializing query params & headers

[vengut]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I used this new .NET 9 attribute to customize enum names and it errors out during request parsing/deserialization:
http://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/customize-properties#custom-enum-member-names

Expected Behavior

I set up my enum like this:

[JsonConverter(typeof(JsonStringEnumConverter))]
public enum TestEnum
{
    [JsonStringEnumMemberName("one")]
    A1,
    [JsonStringEnumMemberName("two")]
    A2,
}

I expected this call to not error out http://localhost:5274/?testEnum=one

All of these work:
http://localhost:5274/?testEnum=A1
http://localhost:5274/?testEnum=0

This also works:

Console.WriteLine(JsonSerializer.Deserialize<TestEnum>("\"one\"")); // A1

Steps To Reproduce

Program.cs:

using System.Text.Json;
using System.Text.Json.Serialization;
using Microsoft.AspNetCore.Mvc;

var builder = WebApplication.CreateBuilder(args);
builder.Services.ConfigureHttpJsonOptions(options =>
{
    options.SerializerOptions.Converters.Add(new JsonStringEnumConverter());
});
var app = builder.Build();

app.MapGet("/", ([FromQuery] TestEnum? testEnum = null) =>
{
    Console.WriteLine(testEnum);
    Console.WriteLine(JsonSerializer.Deserialize<TestEnum>("\"one\""));
    return testEnum;
});

app.Run();

[JsonConverter(typeof(JsonStringEnumConverter))]
public enum TestEnum
{
    [JsonStringEnumMemberName("one")]
    A1,
    [JsonStringEnumMemberName("two")]
    A2,
}

csproj:

<Project Sdk="Microsoft.NET.Sdk.Web">

    <PropertyGroup>
        <TargetFramework>net9.0</TargetFramework>
        <Nullable>enable</Nullable>
        <ImplicitUsings>enable</ImplicitUsings>
    </PropertyGroup>

</Project>

Exceptions (if any)

400

.NET Version

9.0.300

Anything else?

No response

[vengut]

Update:

Parsing from body works fine.

app.MapPost("/", ([FromBody] TestEnum? testEnum = null) =>
{
    Console.WriteLine(testEnum);
    Console.WriteLine(JsonSerializer.Deserialize<TestEnum>("\"one\""));
    return testEnum;
});

However, header doesn't.

app.MapPost("/", ([FromHeader(Name = "test-enum")] TestEnum? testEnum = null) =>
{
    Console.WriteLine(testEnum);
    Console.WriteLine(JsonSerializer.Deserialize<TestEnum>("\"one\""));
    return testEnum;
});

[IBlcl]

Issue confirmed with .NET 9.0.6.
The only workaround found is to use a specific IModelBinder and do the manual conversion there from bindingContext.HttpContext.Request.Query; a bit ugly.