DefaultHandler is not validated at startup

[rido-min]

If I misspell the DefaultHandlerName, the agent with throw an exception on the first message

"UserAuthorization": {
  "DefaultHandlerName": "NotFound",
  "AutoSignin": true,
  "Handlers": {
    "graph": {
      "Settings": {
        "AzureBotOAuthConnectionName": "MCS",
        "Title": "SigIn for Sample",
        "Text": "Please sign in and send the 6-digit code for MCS"
      }
    },
    "github": {
      "Settings": {
        "AzureBotOAuthConnectionName": "GH",
        "Title": "SigIn for Me",
        "Text": "Please sign in and send the 6-digit code for github"
      }
    }
  }
}

System.IndexOutOfRangeException
  HResult=0xFFFF3CA6
  Message=Handler name 'NotFound' not found in configuration under AgentApplication:UserAuthorization:Handlers, or AgentApplication:UserAuthorization:DefaultHandlerName is invalid.
  Source=Microsoft.Agents.Builder
  StackTrace:
   at Microsoft.Agents.Builder.App.UserAuth.UserAuthorization..ctor(AgentApplication app, UserAuthorizationOptions options) in C:\_code\Agents-for-net\src\libraries\Builder\Microsoft.Agents.Builder\App\UserAuth\UserAuthorization.cs:line 87
   at Microsoft.Agents.Builder.App.AgentApplication..ctor(AgentApplicationOptions options) in C:\_code\Agents-for-net\src\libraries\Builder\Microsoft.Agents.Builder\App\AgentApplication.cs:line 65
   at ManualAuthAgent..ctor(AgentApplicationOptions options) in C:\_code\Agents-for-net\src\samples\Authorization\ManualSignIn\ManualAuthAgent.cs:line 14
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
   at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
   at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass2_0.<RealizeService>b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(ServiceIdentifier serviceIdentifier, ServiceProviderEngineScope serviceProviderEngineScope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.<Invoke>d__11.MoveNext()

[tracyboehrer]

I don't understand. That is an intentional throw indicating a config error.

[rido-min]

Can we throw at startup rather than on first message?

[tracyboehrer]

DI doesn't create various things until first use. This behavior would be true for several things. For example, the token providers.

Is there a way to make DI create on registration?