Show help when missing a required parameter about airline

[electrum]

This is an interesting issue. The library was originally designed to be agnostic about the help system. Before the previous release, it was simply another command. This is an important usability problem, so we'll probably need more special casing for help.

[jontodd]

+1 for fixing this issue. If you want to continue to be agnostic to the help system the the Errors object pattern might be a better approach than throwing. Especially when dealing with input from a user which may actually have multiple things wrong with it, this pattern will allow for the reporting of each problem at once rather than failing once at a time.

You could still keep the current semantic you have today with:

MyCommand command = SingleCommand.singleCommand(MyCommand.class).parseFailFast(args);

But then you could also support a model like this:

ParseResult parseResult = new ParseResult();
MyCommand command = SingleCommand.singleCommand(MyCommand.class).parse(args, parseResult);

if (parseResult.hasErrors()) {
   command.helpOption.showHelpWithErrors(parseResult.errors());
}

Thoughts?

[taotaotw]

Seems this fix never goes into the master branch here: https://github.com/airlift/airline Is there any reason?

[hristo-vrigazov]

Any updates on this one?