Multiple subcommands: required option on main command reported missing

[arm-xxl]

I have the following scenario: A CLI with multiple subcommands with the main CLI having required options. Here is what I came up with:

fun main(args: Array<String>) {
    MainCLI().subcommands(Sub1(), Sub2()).main(args)
}

class MainCLI : CliktCommand(allowMultipleSubcommands = true) {
    private val optA: String by option("-a", "--opt-a", help = "My option 'A'").required()

    override fun run() {
        echo("Running main command, optA = $optA")
    }
}

open class SubCLI : CliktCommand() {
    private val optB: String by option("-b", "--opt-b", help = "My option 'B'").default("B")

    override fun run() {
        echo("Running subcommand ${this::class.simpleName}, optB = $optB")
    }
}

class Sub1 : SubCLI()

class Sub2 : SubCLI()

When I run it like this:

main-cli --opt-a=X sub1 --opt-b=Y sub2 --opt-b=Z

I get the following output:

Running main command, optA = X
Running subcommand Sub1, optB = Y
Usage: main-cli [OPTIONS] COMMAND [ARGS]...

Error: Missing option "--opt-a".

I dug a bit with a debugger in hand and got to Parser.parse() It appears it is called several times:

//breakpoint on Line 122
//if (o !is EagerOption && o !in invocationsByOption && (o as? GroupableOption)?.parameterGroup == null) ...

*** Call 1 ***
startingArgI = 0
command -> <MainCLI name=main-cli options=[--opt-a=X --help] subcommands=[<Sub1 name=sub1 options=[--opt-b=null --help]> <Sub2 name=sub2 options=[--opt-b=null --help]>]>
subcommand -> <Sub1 name=sub1 options=[--opt-b=null --help]>

*** Call 2 ***
startingArgI = 2
command -> <Sub1 name=sub1 options=[--opt-b=Y --help]>
subcommand -> null

*** Call 3 ***
startingArgI = 3
command -> <MainCLI name=main-cli options=[--opt-a=X --help] subcommands=[<Sub1 name=sub1 options=[--opt-b=Y --help]> <Sub2 name=sub2 options=[--opt-b=null --help]>]>
subcommand -> <Sub2 name=sub2 options=[--opt-b=null --help]>

Due to my very limited knowledge in kotlin, I got stuck there.
What am I doing wrong?

[ajalt]

Thanks for the clear reproduction! This should be fixed in #191.