Description:
------------
---
From manual page: https://php.net/migration70.changed-functions
---

Usage of the empty function in combination with magic methods that in PHP 5.6 returns false will return true in PHP 7.

The cause is most likely the introduction of the null coalescing operator which causes the empty function to bail early.

When running the test script on PHP 5.6 it will output

Foo::__get(foo)
Foo::__isset(bar)
Foo::__get(bar)
is not empty

and when running on PHP 7 the output will be

Foo::__isset(foo)
is empty

Test script:
---------------
<?php
class Foo {
    public function __get($name) {
        echo __METHOD__ . "($name)" . PHP_EOL;
        switch ($name) {
            case 'foo': return new Foo();
            case 'bar': return 'bar';
            default: return null;
        }
    }

    public function __isset($name) {
        echo __METHOD__ . "($name)" . PHP_EOL;
        return $name === 'bar';
    }
}

$foo = new Foo();
echo (empty($foo->foo->bar) ? 'is empty' : 'is not empty') . PHP_EOL;