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Date: Tue, 2 Mar 2004 20:23:27 -0500
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Subject: more static method fun
From: rrichards@ctindustries.net ("Rob Richards")

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It is currently impossible to call a true static method from within a =
class method. It lets a class method call any object method statically =
even when not defined as a static method.  The static method being =
called inherits the $this from the encapsulating object. This may not be =
a big deal with userspace objects, but it is impossible to handle for =
internal objects.

Within the dom extension there are a few methods which can be called =
both statically and off an instantiated object. Calling them statically =
works fine until they are called within a class method as the function =
either expects this to be defined (meaning an instantiated object) or it =
to be null (when it is called statically). Since within the class =
method, it magically inherits the this of the object calling it, it =
currently crashes.

The following is an example using simplexml to illustrate the problem =
(simplexml's code base is much smaller so easier to follow).
Class AClass {
 function tester() {
  print simplexml_element::asXML(); // segfaults as this should not be =
allowed to be called statically
 }
}

$test =3D new AClass();
$test->tester();

And before someone says that the object type should be tested using =
zend_parse_method_parameters as a "workaround", it still wouldnt work =
correctly:

Class BClass extends simplexml_element {
 function tester() {
  print simplexml_element::asXML();
 }
}

$test =3D new BClass("<root/>");
$test->tester();

This doesnt crash, but because the static call is being called from =
within an object which extends simplexml_element, it would pass and act =
as if $this->asXML() was called, which also is incorrect. It should be =
issuing the same non-static method cannot be called statically error as =
when it is called outside a class. A better example of why it also would =
be incorrect would be using a domdocument:

Class BClass extends domdocument {
 var $newdoc =3D NULL;
 function tester() {
  $this->newdoc =3D domdocument::loadXML("<root/>");
 }
}

$test =3D new BClass();
$test->loadXML("<root>abc</root>");
print $test->saveXML()."\n";
$test->tester();
var_dump($test->newdoc);
print $test->saveXML()."\n";

newdoc ends up as a boolean rather than a new document as $test is =
actually changed from the static call as it believes it is being called =
as $test's method and not as a static method, which should produce a new =
document rather than replacing the current document.

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