EF Core / Postgresql LINQ command is already in progress

ef-core-pg-command-is-already-in-progress.cs

using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");
builder.Services.AddDatabaseDeveloperPageExceptionFilter();
builder.Services.AddDbContext<TestDb>(options =>
    options.UseNpgsql(connectionString).UseLazyLoadingProxies());
builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.UseAuthorization();
app.MapGet("/", async (TestDb db) =>
{
    var result = await db.Cities
    .Include(c => c.Point) // Add this row
    .Select(
        s => new
        {
            Inherit = s.Point, // work
            Point = s.GetPoint(), // not work without Include
        }
    ).ToListAsync();
    return Results.Ok(result);
});
app.MapControllers();

app.Run();

public interface ILocation
{
    public string GetName();
    public double GetX();
    public double GetY();
    public Point GetPoint();
}

public class BaseLocation
{
    [ForeignKey("Point")] public int PointRefId { get; set; }
    public virtual Point Point { get; set; }
}

[Table("point")]
public class Point
{
    [Key] public int Id { get; set; }
    public double X { get; set; }
    public double Y { get; set; }
}

[Table("city")]
public class City : BaseLocation, ILocation
{
    [Key] public int Id { get; set; }
    public string Name { get; set; }

    public double GetX()
    {
        return Point.X;
    }

    public double GetY()
    {
        return Point.Y;
    }

    public Point GetPoint()
    {
        return Point;
    }

    public string GetName()
    {
        return Name;
    }
}

class TestDb : DbContext
{
    public TestDb(DbContextOptions<TestDb> options) : base(options)
    {
    }

    public DbSet<Point> Points { get; set; }
    public DbSet<City> Cities { get; set; }
}