Service Stack crashes on parsing command line arguments when duplicate key is present

Reproduce: Have a .NET 6.0 executable project with ServiceStack running inside ASP.NET (with using .UseKestrel()) and one service of any kind, smth similar to:

var host = new WebHostBuilder()
    .UseConfiguration(config)
    .UseContentRoot(Directory.GetCurrentDirectory())
    .UseKestrel(options =>
    {
        options.Listen(IPAddress.Parse(advertiseAddress),
            listenPort,
            listenOptions =>
            {
                listenOptions.UseConnectionLogging("HTTP");
                listenOptions.NoDelay = true;
            });
    })
    .UseStartup<Startup>()
    .Build();

And in Startup:

public class IriskaAspStartup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc();
    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
    {
        var publishDirectory = GetPublishDirectory(env);
        RegisterServiceStackLicense();
        var appHost = CreateServiceStackAppHost(ioc);

        app.UseServiceStack(appHost);
        app.UseStaticFiles();
        ...
    }

    ...
}

Run the executable with duplicated keys in the call, for example:

dotnet app.dll --configDir=/firstConfigDir --configDir=/secondConfigDir

Expected ServiceStack doesn't try to intercept arguments, so nothing crashes when launching the application or accessing a service.

Observed Hard crash with call to Environment.Exit() from AppTasks class because ServiceStack assumes two things: the format of command line arges starting with -- or / and separated with =, and that there are no duplicate keys (call to .ToDictionary).

Offending line: https://github.com/ServiceStack/ServiceStack/blob/7e51d4a8080cd4818be00f9cfb5a44b83c44e6a3/ServiceStack/src/ServiceStack.Common/AppTasks.cs#L64

And much more suprisingly the fact that https://github.com/ServiceStack/ServiceStack/blob/7e51d4a8080cd4818be00f9cfb5a44b83c44e6a3/ServiceStack/src/ServiceStack.Common/AppTasks.cs#L124 kills the app although ServiceStack is an applicative library.

Proposition Allow duplicate arguments OR event better don't assume anything about the application's command line arguments format OR at least swallow exception and assume no --AppTasks arg is passed (https://github.com/ServiceStack/ServiceStack/blob/7e51d4a8080cd4818be00f9cfb5a44b83c44e6a3/ServiceStack/src/ServiceStack.Common/AppTasks.cs#L65). In my opinion, the way the application manages command line must never be responsibility of an applicative lib.

Many application allow duplicate cmd args keys (example: docker -v /vol1:/vol1 -v /vol2:vol2).

ServiceStack / Issues

Service Stack crashes on parsing command line arguments when duplicate key is present #791