Description:
------------
I have an object when I override __get and __isset. I try to use __isset but it seems that the __get is called before __isset. It's not the same thing with arrays (I can do isset($someArray['existingParentKey']['notExistingChildKey']) or isset($someArray['notExistingParentKey']['notExistingChildKey']) without problem.

I added multiple examples and comments to show it.

Maybe it's the expected behaviour. The __get should try __iset before trying to get the value, but it doesn't seem logical.

It might be a duplicate of #72056 (__get is called for testing if chained property is set)

Test script:
---------------
<?php

class Config
{
    
    protected static $data;
    
    public static function init() {
        self::$data = new \StdClass();
        self::$data->parent = new \StdClass();
    }
    
    public function __get($key) {
        return self::$data->$key;
    }
    
    public function __isset($key) {
        return(isset(self::$data->$key));
    }
    
}

$config = new Config();

// prints "is set", as expected
if(isset($config->parent)) {
    echo 'is set' . PHP_EOL;
}
else {
    echo 'not set' . PHP_EOL;
}

// should print "not set" but throws an exception before
if(isset($config->parent->notChild)) {
    echo 'isset' . PHP_EOL;
}
else {
    echo 'not set' . PHP_EOL;
}

// prints "not set"
if(isset($config->notParent)) {
    echo 'is set' . PHP_EOL;
}
else {
    echo 'not set' . PHP_EOL;
}


// should write "not set" but throws an exception before
if(isset($config->notParent->test)) {
    echo 'is set' . PHP_EOL;
}
else {
    echo 'not set' . PHP_EOL;
}


Expected result:
----------------
The __isset should be called recursively before trying to __get the child element.

Actual result:
--------------
An exception is thrown, making the __isset useless.