To me it is obvious hooks won't use other hooks because that could lead to an infinite loop in a hurry
> Does reading `$this->countryCode` use the getter hook, even it's from a `countryCode` hook?
same
> If not, is there a way to call the `countryCode` getter from this setter?
There is although it's a bit tricky and not intuitive but I feel this falls under the "it is enough this is possible, there's no need for it to be easy": "Be aware, the detection logic works on $this->[propertyName] directly at compile time, not on dynamic forms of it like $prop = 'beep'; $this->$prop. That will not trigger a backing value." Using dynamic properties in what should be simple code should be rare enough this is not a problem. It's like a bridge convention, the benefits vastly outweigh the drawbacks.