Is CommandLineApplication.Parse supposed to trigger validation?

[thomaslevesque]

I'm using CommandLineUtils to parse command line options, but I don't want to use the library's execution engine, because I don't want to refactor the existing code to fit that model. So I'm using the Parse method like this:

        var app = new CommandLineApplication(throwOnUnexpectedArg: false);
        var configurationOption = app.Option<string>(
            "-c|--configuration",
            "The build configuration",
            CommandOptionType.SingleValue,
            option => option.Accepts(builder => builder.Values("Debug", "Release")));
        app.Parse(args);
        var configuration = configurationOption.HasValue() ? configurationOption.Value() : "Release";

However, option.Accepts(builder => builder.Values("Debug", "Release")) seems to have no effect. It looks like validation isn't run. Is this the expected behavior? If not, how could I achieve what I'm trying to do?

I know I could just check the value manually, but I was hoping to take advantage of CommandLineUtils' validation mechanism.

[natemcmaster]

Yes, this is the expected behavior. If you want to run validation manually, you can do this:

var parseResult = app.Parse(args);
var validationResult = parseResult.SelectedCommand.GetValidationResult();

FYI checkout what CommandLineApplication.Execute does:

CommandLineUtils/src/CommandLineUtils/CommandLineApplication.cs

Lines 695 to 712 in 2753a1c

	public int Execute(params string[] args)
	{
	var parseResult = Parse(args);
	var command = parseResult.SelectedCommand;
	if (command.IsShowingInformation)
	{
	return HelpExitCode;
	}
	var validationResult = command.GetValidationResult();
	if (validationResult != ValidationResult.Success)
	{
	return command.ValidationErrorHandler(validationResult);
	}
	return command.Invoke();
	}

[thomaslevesque]

Thanks!

[ai-fwd]

@natemcmaster / @thomaslevesque GetValidationResult() is internal so it's not accessible. Am I missing something?

[natemcmaster]

That's a very good point. Do you need to run validation manually?

[ai-fwd]

@natemcmaster yes ideally I do. I'm doing something a little non-standard in that I'm using your library to build out a Slack App. Essentially in my scenario the command line is Slack. Commands need to be parsed and validated before being added to a queue for processing.