I have a Dagger function that looks like this:
func (m *Beeps) Build(
ctx context.Context,
source *dagger.Directory,
// +optional
release bool,
) *dagger.Container {
I'd like the source argument to be optional—it's uniformly . on the CLI—but I don't see a good way to do that in the docs. Am I missing something? Is there some security rule where you have to explicitly specify the directory you want to build from?