Telling Configuration-binding source generator to ignore certain members

[jamescrosswell]

I'm trying to modify some existing code so that this compiles with <IsAotCompatible>true</IsAotCompatible>. We have some "Options" classes that have a mix of some things that you might want to store in a config file like appsettings.json (primatives like bool, int, string) and some other stuff that you would definitely supply at runtime (e.g. callback methods).

After enabling source genators (with <EnableConfigurationBindingGenerator>true</EnableConfigurationBindingGenerator>), unsurprisingly, I get a bunch of errors related to the type members that aren't designed to be read from config).

A trivial example to reproduce the problem:

using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Options;

var builder = new ConfigurationBuilder()
    .SetBasePath(Directory.GetCurrentDirectory())
    .AddJsonFile("AppSettings.json");

var config = builder.Build();

var appConfig = config.GetSection("Settings").Get<AppSettings>();

Console.WriteLine(appConfig?.ExampleString);
Console.WriteLine(appConfig?.Number);

public class AppSettings
{
    public string? ExampleString { get; set; }
    public int? Number { get; set; }
    // Uncomment the following to break source generation...   
    // public Func<string, string>? ExampleStringTransform { get; set; }
}

Is there a mechanism to tell the GeneratedConfigurationBinder to ingore certain members on the type being bound or is there some other way to solve this?