showDefaultValues=true plus defaultValueProvider does not render defaultValues in usage help

Specifying the default value of an option via an IDefaultValueProvider and setting showDefaultValues = true does not display the default vaulue as part of the standard usage help.

Example Code:

@Command(name = "foo", //
    mixinStandardHelpOptions = true, //
    defaultValueProvider = FooCommandDefaultValueProvider.class, //
    showDefaultValues = true, //
)
public class FooCommand implements Runnable {

    public static class FooCommandDefaultValueProvider implements IDefaultValueProvider {
        @Override
        public String defaultValue(final ArgSpec argSpec) throws Exception {
            if ("DURATION".equals(argSpec.paramLabel())) {
                return "1200";
            }
            return null;
        }
    }

    @Option( //
        names = {"-d", "--duration"}, paramLabel = "DURATION", //
        description = { "The duration, in seconds." }, //
        arity = "1", //
        required = false //
    )
    protected Integer duration;
}

Only when I additionally set @Option(showDefaultValue=Help.Visibility.ALWAYS) for the respective option the value is displayed or when I explicitly set a default value directly via @Option(defaultValue="1200")

[remkop]

Picocli 3.9.3 has been released. This includes a fix for this issue.

Enjoy!

[remkop]

I found the cause. In ArgSpec.internalShowDefaultValue(boolean) the logic checks whether a default value exists, and this does not take the defaultValueProvider into account.

I’ll have a fix for this shortly.