Description:
------------
I want to create a class that mimics arrays, but has full control over itself, i.e., whenever a property is updated/set, it knows.

Basically I want to use this to cache this array in memory persistently, and update the cache on the fly when updated.

Using a custom class with __get, __set, or using ArrayAccess, or using SPL ArrayObject did not enable me to get past this simple limitation.

PHP implicitly creates a stdClass when you do

$obj->a->b='something';

But does not invoke set or get on $obj with key "a". Even if a stdClass is initiated, one would expect it to hold the value, then be passed to set(). Or one would expect a stdClass to be created, then get() used to retrieve it for modifications.

There is basically no way to notice such behavior from within the class. Even an error handler, although recognizing this happenning, can not access the properties.

Test script:
---------------
class MyArrayObject extends ArrayObject
{
	function __construct($input=[])
	{
		parent::__construct($input,ArrayObject::ARRAY_AS_PROPS);
	}
	function offsetSet($x,$v)
	{
		echo "offsetSet('{$x}')\n";
		return parent::offsetSet($x,$v);
	}
	function &offsetGet($x)
	{
		echo "offsetGet('{$x}')\n";
		$t=parent::offsetGet($x);
		return $t;
	}
	function __get($x)
	{
		echo "__get('{$x}')\n";
	}
	function __set($x,$v)
	{
		echo "__set('{$x}')\n";
	}
	function offsetExists($x)
	{
		echo "offsetExists('{$x}')\n";
		return parent::offsetExists($x);
	}
}
$x=new MyArrayObject;
$x->hello=5;
$x['hi']=10;
$x['hello']++;
@$x->a->b=7;
$x->a->b++;
var_dump($x);


Expected result:
----------------
either set() or get() being called.

Actual result:
--------------
No call.