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Doc Bug #47765 __invoke lacks if object is a static property or return
Submitted: 2009-03-24 19:10 UTC Modified: 2009-11-19 13:23 UTC
Votes:1
Avg. Score:5.0 ± 0.0
Reproduced:0 of 0 (0.0%)
From: biohazard999 at gmx dot at Assigned:
Status: Not a bug Package: Documentation problem
PHP Version: 5.3.0RC1 OS: *
Private report: No CVE-ID: None
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From: biohazard999 at gmx dot at
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 [2009-03-24 19:10 UTC] biohazard999 at gmx dot at 
Description:
------------
If the object to invoke is stored in a static property or is returned by a static function __invoke will not be called.
Especially for singletons is this extremly missleading.

Either it is an documentation problem or something other is wrong.

Actual documentation:
The __invoke method is called when a script tries to call an object as a function. 

Reproduce code:
---------------
class foo
{
  public static $instance = null; //only public for this example

  public static function get()
  {
    if(is_null(self::$instance))
      self::$instance = new self;

    return self::$instance;
  }

  public function __invoke($name)
  {
    echo 'Hello '.$name;
  }
}

//1)
foo::get()('World');

//2)
foo::get();
foo::$instance('World');

//3)
$bar = foo::get();
$bar('World');

Expected result:
----------------
1) //Here is the parsing-error partial expected
Hello World

2)
Hello World

3)
Hello World

Actual result:
--------------
1)
Parse error: parse error in test.php on line 23

2)
Notice: Undefined variable: instance in test.php on line 27
Fatal error: Function name must be a string in test.php on line 27

3)
Hello World //Behavior as expected

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 [2009-06-18 15:18 UTC] pajoye@php.net 
not windows specific
 [2009-11-19 11:24 UTC] vrana@php.net 
It's because of priority:
<?php
$instance = "f";
foo::$instance('World'); // calls foo::f('World')
?>

$instance('World') has higher priority than foo::$instance.
 [2009-11-19 13:23 UTC] biohazard999 at gmx dot at 
There is no method called "f". I'm talking about a static member variable.

So you can't invoke a static member variable as function.
There is NO hint in the documentation you can't call a object thats returned by a method or holden in a static member var as a function.

Check the docs:
The __invoke method is called when a script tries to call an object as a function. 

$anObject(); //calls: __invoke
$this->anObject(); //calls: __invoke
AClass::$anObject(); //throws: Fatal error?! there is no static member "anObject". 
AClass::methodReturningAnObject()() //should: call the __invoke operation on the returned object. throws: parsing error

$anObject = AClass::methodReturningAnObject();
$anObject(); //calls: __invoke(); -> works like the first example.


$member = 'methodReturningAnObject';
$anObject = AClass::$member(); // calls AClass::methodReturningAnObject(); returns: $anObject.
$anObject(); //calls: __invoke(); -> works like the first example.

BUT:
AClass::$member()(); //should: call the __invoke operation on the returned object. throws: parsing error.

Thats all logical, but not documentated. 
An object is still a object, independent from the "storing point"
This is a documentation problem. Not a bogus.
 
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