Cannot use System.Text.Json Source Generator fast path serialization in ASP.NET Core Minimal API

[Stepami]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

JsonContext set up for fast path serialization (GenerationMode = JsonSourceGenerationMode.Serialization) fails to serialize responses from API methods in ASP NET Core application.
The error disappears if GenerationMode is not JsonSourceGenerationMode.Serialization

Expected Behavior

200 OK, serialized response and no exceptions thrown

Steps To Reproduce

using System.Text.Json.Serialization;

var builder = WebApplication.CreateSlimBuilder(args);

builder.Services.ConfigureHttpJsonOptions(options =>
{
    options.SerializerOptions.TypeInfoResolverChain.Insert(0, AppJsonSerializerContext.Default);
});

Todo[] sampleTodos =
[
    new(1, "Walk the dog"),
    new(2, "Do the dishes", DateOnly.FromDateTime(DateTime.Now)),
    new(3, "Do the laundry", DateOnly.FromDateTime(DateTime.Now.AddDays(1))),
    new(4, "Clean the bathroom"),
    new(5, "Clean the car", DateOnly.FromDateTime(DateTime.Now.AddDays(2)))
];

var app = builder.Build();
app.MapGet("/todos", () => sampleTodos);
app.Run();

public record Todo(int Id, string? Title, DateOnly? DueBy = null, bool IsComplete = false);

[JsonSerializable(typeof(Todo[]))]
[JsonSourceGenerationOptions(GenerationMode = JsonSourceGenerationMode.Serialization)]
internal partial class AppJsonSerializerContext : JsonSerializerContext;

Exceptions (if any)

fail: Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware[1]
      An unhandled exception has occurred while executing the request.
      System.InvalidOperationException: TypeInfoResolver '[AppJsonSerializerContext]' did not provide property metadata for type 'Todo'.
         at System.Text.Json.ThrowHelper.ThrowInvalidOperationException_NoMetadataForTypeProperties(IJsonTypeInfoResolver resolver, Type type)
         at System.Text.Json.Serialization.Converters.ObjectDefaultConverter`1.OnTryWrite(Utf8JsonWriter writer, T value, JsonSerializerOptions options, WriteStack& state)
         at System.Text.Json.Serialization.JsonConverter`1.TryWrite(Utf8JsonWriter writer, T& value, JsonSerializerOptions options, WriteStack& state)
         at System.Text.Json.Serialization.Converters.ArrayConverter`2.OnWriteResume(Utf8JsonWriter writer, TElement[] array, JsonSerializerOptions options, WriteStack& state)
         at System.Text.Json.Serialization.JsonCollectionConverter`2.OnTryWrite(Utf8JsonWriter writer, TCollection value, JsonSerializerOptions options, WriteStack& state)
         at System.Text.Json.Serialization.JsonConverter`1.TryWrite(Utf8JsonWriter writer, T& value, JsonSerializerOptions options, WriteStack& state)
         at System.Text.Json.Serialization.JsonConverter`1.WriteCore(Utf8JsonWriter writer, T& value, JsonSerializerOptions options, WriteStack& state)
         at System.Text.Json.Serialization.Metadata.JsonTypeInfo`1.SerializeAsync(Stream utf8Json, T rootValue, CancellationToken cancellationToken, Object rootValueBoxed)
         at System.Text.Json.Serialization.Metadata.JsonTypeInfo`1.SerializeAsync(Stream utf8Json, T rootValue, CancellationToken cancellationToken, Object rootValueBoxed)
         at System.Text.Json.Serialization.Metadata.JsonTypeInfo`1.SerializeAsync(Stream utf8Json, T rootValue, CancellationToken cancellationToken, Object rootValueBoxed)
         at Microsoft.AspNetCore.Http.HttpResponseJsonExtensions.<WriteAsJsonAsync>g__WriteAsJsonAsyncSlow|5_0[TValue](HttpResponse response, TValue value, JsonTypeInfo`1 jsonTypeInfo)
         at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

.NET Version

9.0.200

[BrennanConroy]

That's by design dotnet/docs#44413
Whether it's a good design or not is debatable.

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