How to configure a prompt with a default that comes from another option?

I’m trying to setup a command that takes multiple sets of credentials (for different things) as options. All of them can be prompted for, but I would like the first username to be shown and used as default value for other username prompts.

class MyCommand : CliktCommand() {

    val githubUser by option("--github-user").prompt("Your GitHub username")

    val bintrayUser by option("--bintray-user").prompt("Your Bintray username", default = githubUser)
}

This obviously doesn’t work because githubUser doesn’t have a value at this time. Is there a way to provide a default with a lambda?

[ajalt]

Jake is right, you can use defaultLazy here. option().prompt() just calls TermUi.prompt under the hood, so you can do the same:

class MyCommand : CliktCommand() {
    val githubUser by option("--github-user").prompt("Your GitHub username")
    val bintrayUser by option("--bintray-user").defaultLazy {
        TermUi.prompt("Your Bintray username", default = githubUser) ?: githubUser   
    }
}

There’s a caveat that default values (including prompt()) are evaluated in the order they’re defined, so make sure you’re only referencing properties defined earlier in the command. If you don’t want to rely on the definition order, you can call TermUi.prompt manually from run.

[joffrey-bion]

That makes sense. I was somehow too focused on the prompt() shorthand. Thanks!