Initializing class property in get hook does not call set hook

[everstead-it]

Description

The following code:

<?php

class Deferred {
    // 
}

class Test {
    protected(set) array $loaded = [];
    
    protected(set) Deferred $instance {
        get => $this->instance ??= new Deferred();
        set {
            $this->instance = $value;
            $this->loaded[$value::class] = $value;
        }
    }
}

$test = new Test();

$instance = $test->instance;
var_dump($test->loaded);

Resulted in this output:

array(0) {
}

But I expected this output instead:

array(1) {
  ["Deferred"]=>
  object(Deferred)#? (0) {
  }
}

Here is the 3v4l.org link.

Is this expected behavior? I wanted to defer loading some objects until the property is requested, but I need to register them with a container instance whenever they are set.

PHP Version

PHP 8.4.1

Operating System

Ubuntu 22.04

[nielsdos]

I think this is the correct behaviour.
When in a hook context, hooks are bypassed to allow raw property access.
In this case you can split the common setting part off to a separate function and call that from both the getter and setter hook.

[everstead-it]

Ok, understandable. I know raw property access is needed in the set hook for obvious reasons, but was thinking the get hook was safe to call set. Was hoping to avoid a setter function, but it makes sense.

I guess the null assignment check in the getter needs the raw value anyway to work. I was thinking it would trigger based on the property never being access before (so uninitialized/null) but it makes more sense the backing value is uninitialized/null in the get hook context. Thanks for the quick response.