gistfile1.php

<?php

#
# Even if the $bar property is private, it can be accessed publicly and modified by the modify() method
# that modifies an instance of the same PHP class.
#

class Foo
{
    private $bar;

    public function __construct($bar)
    {
	$this->bar = $bar;
    }

    public function modify(Foo $foo)
    {
        $foo->bar = 'C';
    }
}

$a = new Foo('A');
$b = new Foo('C');
$b->modify($a);

# $a->bar now equals 'C'
var_dump($a);

That actually makes sense, so I wouldn't count it as a phpsadness. I agree it feels a bit counterintuitive, because the visibility is class-level instead of object-level. I wrote about it a few months back: http://blog.verraes.net/2011/03/accessing-private-properties-from-other-instances/

Thanks for your blog post.