Add support for reading default scheme from config

src/Security/Authentication/Core/src/AuthenticationBuilder.cs

@@ -32,10 +32,6 @@ public AuthenticationBuilder(IServiceCollection services)
         where THandler : class, IAuthenticationHandler
     {
         var state = new AddSchemeHelperState(typeof(THandler));
-        // Don't read global authentication options until an
-        // authentication scheme has been configured to avoid
-        // prematurely registering options
-        Services.TryAddEnumerable(ServiceDescriptor.Singleton<IConfigureOptions<AuthenticationOptions>, AuthenticationConfigureOptions>());
         Services.Configure<AuthenticationOptions>(o =>
         {
             o.AddScheme(authenticationScheme, scheme =>

src/Security/Authentication/Core/src/AuthenticationConfigurationProviderExtensions.cs

@@ -20,6 +20,13 @@ public static class AuthenticationConfigurationProviderExtensions
     /// <returns>The specified <see cref="IConfiguration"/> object, or null if the requested section does not exist.</returns>
     public static IConfiguration GetSchemeConfiguration(this IAuthenticationConfigurationProvider provider, string authenticationScheme)
     {
+        ArgumentNullException.ThrowIfNull(provider, nameof(provider));
+
+        if (provider.AuthenticationConfiguration is null)
+        {
+            throw new InvalidOperationException("There was no top-level authentication property found in configuration.");
+        }
+
         return provider.AuthenticationConfiguration.GetSection($"{AuthenticationSchemesKey}:{authenticationScheme}");
     }
 }

src/Security/Authentication/Core/src/AuthenticationServiceCollectionExtensions.cs

@@ -3,6 +3,7 @@
 
 using Microsoft.AspNetCore.Authentication;
 using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Options;
 
 namespace Microsoft.Extensions.DependencyInjection;
 
@@ -28,6 +29,8 @@ public static AuthenticationBuilder AddAuthentication(this IServiceCollection se
         services.AddWebEncoders();
         services.TryAddSingleton<ISystemClock, SystemClock>();
         services.TryAddSingleton<IAuthenticationConfigurationProvider, DefaultAuthenticationConfigurationProvider>();
+        services.TryAddEnumerable(ServiceDescriptor.Singleton<IConfigureOptions<AuthenticationOptions>, AuthenticationConfigureOptions>());
+
         return new AuthenticationBuilder(services);
     }
 

src/Security/Authentication/test/RemoteAuthenticationTests.cs

@@ -5,6 +5,7 @@
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.TestHost;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 
@@ -18,6 +19,7 @@ private Task<IHost> CreateHost(Action<TOptions> configureOptions, Func<HttpConte
         => CreateHostWithServices(s =>
         {
             var builder = s.AddAuthentication();
+            s.AddSingleton<IConfiguration>(new ConfigurationManager());
             if (isDefault)
             {
                 s.Configure<AuthenticationOptions>(o => o.DefaultScheme = DefaultScheme);