php no overloading inside static function

Question

i dont seem to understand why the code below only prints "TEST" two times.

<?php

class A {
    private $test = "TEST<br />";

    public static function getInstance() {
        return new self();
    }

    public static function someStaticMethod() {
        $a = new self();
        $a->test;
    }

    public function __get($args) {
        echo $this->$args;
    }
}

/* echo's "TEST" */
$a = new A();
$a->test;

/* echo's "TEST" */
$a2 = A::getInstance();
$a2->test;

/*
No output... eeerhm... how come?
Why is $a->test (inside someStaticMethod()) not being overloaded by __get ??
*/
A::someStaticMethod();

?>

PHP site says (link):

Property overloading only works in object context. These magic methods will not be triggered in static context. Therefore these methods should not be declared static. As of PHP 5.3.0, a warning is issued if one of the magic overloading methods is declared static.

But i think they are trying to say u should declare the magic methods static. e.g.:

public static function __get(){}

Plus the fact the i am in fact using it in object context. $a = new self(); returns an instance from class A in variable $a. Then i am using $a->test (object context imo?) to fetch the private "test" variable which in turn should get overloaded...

i am confused...

JvdBerg · Accepted Answer · 2012-09-06 19:28:15Z

3

From the manual:

The overloading methods are invoked when interacting with properties or methods that have not been declared or are not visible in the current scope.

When your are calling the static method someStaticMethod() the private $test is visible in the current scope, so the magic __get method is not called.

edited Sep 6, 2012 at 19:28

answered Sep 6, 2012 at 19:21

JvdBerg

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2 Comments

Marc Over a year ago

if i could i would vote both of youre anwers as the accepted one. :( . But how would i be able to access $test from the static method someStaticMethod() ?? I get that it is "visible in the current scope". But i cant access instance context from static context right? So practically i wont be able to access $test directly from someStaticMethod() right? Anywayz... this is a bit a pain in the *ss since i am using the overloading for lazy loading. So this is pretty anoying to me... any workarounds for it?

bfavaretto Over a year ago

@Marc You can't, but I upvoted this answer to give it the due credit. We reached the same conclusion by different means.

Community · Accepted Answer · 2023-11-17 19:24:28Z

2

It seems that, in the context of A:: someStaticMethod, PHP allows you to access the private variable $test directly, so the magic method is not executing. If you echo $a->test; from there, you'll see it's being accessed.

That is the expected behaviour, according to the PHP Manual:

Objects of the same type will have access to each others private and protected members even though they are not the same instances. This is because the implementation specific details are already known when inside those objects.

edited Nov 17, 2023 at 19:24

CommunityBot

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answered Sep 6, 2012 at 19:25

bfavaretto

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