I don't understand the purpose of code snippet

Question

In Zend Frameword 2.5 a review and saw some code, it works fine but my IDE shows error about it. I don't know purpose of this code snippet. Why to write: $this->table = clone $this->table;

Github Link: https://github.com/zendframework/zend-db/blob/master/src/TableGateway/AbstractTableGateway.php

Function: rows 529-544

Please explain to me about it.

public function __clone()
    {
        $this->resultSetPrototype = (isset($this->resultSetPrototype)) ? clone $this->resultSetPrototype : null;
        $this->sql = clone $this->sql;
        if (is_object($this->table)) {
            $this->table = clone $this->table;
        } elseif (
            is_array($this->table)
            && count($this->table) == 1
            && is_object(reset($this->table))
        ) {
            foreach ($this->table as $alias => &$tableObject) {
                $tableObject = clone $tableObject;
            }
        }
    }

Answer 1

I can't understand Zend purpose but i hope after run two below code snippet, from different two results, you can understand

<?php
class A {
    public $foo = 1;
}  

class B {
    protected $value = 1;
    protected $bar = null;//
    public function __construct() {
      $this->bar = new A();
    }

    public function setValue($foo = 3){
      $this->value = $foo;
    }

    public function setFooBar($foo = 3){
      $this->bar->foo = $foo;
    }

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

$a = new B();
$c = clone($a);
$c->setFooBar(3);
$c->setValue(6);
var_dump($a);
echo "\n";
var_dump($c);
?>

<?php
class A {
    public $foo = 1;
}  

class B {
    protected $value = 1;
    protected $bar = null;//
    public function __construct() {
      $this->bar = new A();
    }

    public function setValue($foo = 3){
      $this->value = $foo;
    }

    public function setFooBar($foo = 3){
      $this->bar->foo = $foo;
    }
}

$a = new B();
$c = clone($a);
$c->setFooBar(3);
$c->setValue(6);
var_dump($a);
echo "\n";
var_dump($c);
?>