code igniter develop : function load_class

CI3_ref_is_not_necessary.php

<?php

/**
 * @see : https://github.com/bcit-ci/CodeIgniter/blob/develop/system/core/Common.php#L141
 * Return a reference is useless !
 * To explain : https://youtu.be/_84eIkA3j54?t=13m48s
 */

//Code example:

//Create a Foo class with a attribute
class Foo
{
	protected $attr;
	
	public function __construct($attr)
	{
		$this->attr = $attr;
	}
}

//Declare function without return reference
function loadclass() {
	$foo = new Foo('bar'); //Instance Foo with bar attribute
	echo 'Foo1 : ';
	var_dump($foo); //Display Foo instance from the fonction
	echo '<br>';
	
	return $foo;
}

//Declare function with return reference like code igniter
function &loadClass2() {
	$foo = new Foo('baz'); //Instance Foo with bar attribute
	echo 'Foo2 : ';
	var_dump($foo); //Display Foo instance from the fonction
	echo '<br>';
	
	return $foo;
}

$foo1 = loadClass(); //Get the Foo instance without reference
$foo2 = &loadClass2(); //Get the Foo instance with reference

//Display Foo instances
echo '<br>';
echo 'Foo1 return : ';
var_dump($foo1);
echo '<br>';
echo 'Foo2 return : ';
var_dump($foo2);

//Display zval object
echo '<br><br>';
debug_zval_dump($foo1);
echo '<br><br>';
debug_zval_dump($foo2);


/**
 * From PHP 5.2 to PHP 7.0, the result is : 
 * 
 * Foo1 : object(Foo)#1 (1) { ["attr":protected]=> string(3) "bar" } 
 * Foo2 : object(Foo)#2 (1) { ["attr":protected]=> string(3) "baz" } 
 * 
 * Foo1 return : object(Foo)#1 (1) { ["attr":protected]=> string(3) "bar" } 
 * Foo2 return : object(Foo)#2 (1) { ["attr":protected]=> string(3) "baz" } 
 * 
 * object(Foo)#1 (1) refcount(2){ ["attr":protected]=> string(3) "bar" refcount(1) } 
 * 
 * object(Foo)#2 (1) refcount(2){ ["attr":protected]=> string(3) "baz" refcount(1) }
 */
// The both Foo object save they instance. The reference is useless.
// View the youtube link to understand why. The table at that time explain how PHP save instance in memory.