Behaviour doesn't match documentation for boolean Option arity

[joca-bt]

https://picocli.info/apidocs/picocli/CommandLine.Option.html#arity-- says:

• By default, flags (boolean options) have arity zero
• By default picocli does not expect boolean options (also called "flags" or "switches") to have a parameter.

However specifying a parameter is not resulting in error by default:

@Command(name = "test")
public class Main implements Runnable {
    @Option(names = { "--option" })
    private boolean option;

    @Override
    public void run() {
    }

    public static void main(String[] args) {
        int exitCode = new CommandLine(new Main()).execute(args);
        System.exit(exitCode);
    }
}

The error only appears when we explicitly add arity = "0" to the above @Option declaration:

option '--option' (<option>) should be specified without 'true' parameter

which, by the documentation, should already be the default.

[remkop]

You are correct, the documentation is incorrect.
The default arity for boolean options is actually "0..1" now.

Do you feel like contributing a pull request for this?

[joca-bt]

Revert the code behaviour or doc?

[remkop]

We’ll change the documentation.
There’s no reason to break existing applications that depend on the current behaviour. :-)