PHP Class Scope confusing with call_user_func()

Question

class A
{
    public static function who1()
    {
        var_dump(get_called_class());
    }
}
class B extends A
{
    public static function who2()
    {
        parent::who1();
    }
}
call_user_func(array('B', 'parent::who1'));
B::who2();

What I expect:

string 'B' (length=1)

string 'B' (length=1)

Actual returns:

boolean false

string 'B' (length=1)

Can anyone tell me why the output is different from what I expected?

see also:

https://www.php.net/manual/en/language.types.callable.php

https://www.php.net/manual/en/function.get-called-class.php

edit: Maybe my old code is not clear, here is the new example:

class A
{
    public static function who()
    {
        var_dump(get_called_class());
    }
}
class B extends A
{
    public static function who()
    {
        echo 'hehe';
    }
}
call_user_func(array('B', 'parent::who'));

why it output false?

You don't need to add the parent part in the call to parent::who1. Have a look at php.net/manual/en/language.oop5.inheritance.php: For example, when you extend a class, the subclass inherits all of the public and protected methods from the parent class. Unless a class overrides those methods, they will retain their original functionality. — Andrew Mackrodt
– Andrew Mackrodt, Commented Feb 15, 2014 at 17:35

BlitZ · Accepted Answer · 2014-02-15 18:02:16Z

2

From the PHP manual documentation for Object Inheritance:

For example, when you extend a class, the subclass inherits all of the public and protected methods from the parent class. Unless a class overrides those methods, they will retain their original functionality.

As stated above, there is no need of parent prefix there in call_user_func():

call_user_func(array('B', 'who'));

You got FALSE in var_dump() because call_user_func() stated method call outside a class. So get_called_class() behaved as expected (or mentioned in the manual):

Returns FALSE if called from outside a class.

edited Feb 15, 2014 at 18:02

answered Feb 15, 2014 at 17:34

BlitZ

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3 Comments

Eathen Nutt Over a year ago

I don't get it. get_called_class() is still inside method who(), who() is inside class A. If I call it like this A::who(); it will output A.

BlitZ Over a year ago

@nut get_called_class() probably in this case can not properly determine caller class. And this seems like a bug to me. Looks like call_user_func(array('B', 'parent::who')); forces ::who() to be called outside a class scope.

Eathen Nutt Over a year ago

Yea, my example seems complex, I will post it on bug list to get the detailed information. And thanks for mention Object Inheritance

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