`-` value seem not to work when passed to `Option.String` as option

[jeremiegirault]

Hello and first thank you for the good work on this library.

I wanted to report an issue that I found while working a small utility :
I wanted to add an option to my tool which can optionally take - as value (a pattern commonly seen on cli tools for redirecting some output on stdout instead of a file)

class BuildContextCommand extends clipanion.Command {
    public static paths = [ [ 'docker', 'build-context' ] ]
    public static usage = {
      description: 'builds an efficient docker context .tgz from a yarn workspace'
    }

    public output = clipanion.Option.String(`-o,--output`, {
      description: `the tgz output, use '-' to write contents to stdout (useful for piping to docker)`,
      required: false
    })
    public execute = async () => { console.log(this.output) }
}

clipanion seem to fail not recognizing this value:

hb docker build-context -o -
Unknown Syntax Error: Not enough arguments to option -o.

$ hb docker build-context [-o,--output #0] [input]

It's working when using the = form though:

hb docker build-context -o=-
-

maybe it's interpreted as another (positional/option) argument ?

macos 11.3
node v14.15.4
clipanion: 3.0.0-rc.12

Thank you,

[cspotcode]

I'm hitting this as well. I assume the fix is to treat any argv entry that is - as being a string, not a flag.

The only ambiguity would be if you wanted to declare an optional flag that was named '' (empty string) like this:

  thisOptionHasEmptyName: Option.String('-')

I'm not sure if that works and I'm pretty sure it should not be supported, but maybe there are CLIs that need this feature?

[arcanis]

Yep, I think it'd be fine to special-case - out of the options ("empty option" is already prevented by the regexp). It should only be a matter of replacing the startsWith calls with an helper that checks for "t".

[arcanis]

Should be fixed in 3.0.0.