is_a() triggers __autoload() in 5.3.7 View as Markdown

Hi.

After upgrading to php 5.3.7, whenever I use is_a($object, 'ClassName');
the autoloader of classes is now called.

This did not happen in earlier versions of php 5.3 that I used before.
But I cannot find any mention of it anywhere, no open bugs for it, and
nothing in the changelogs.

Is it a bug or is it intentional that it has started behaving this way?

--
Mads Lie Jensen - mads@gartneriet.dk - ICQ #25478403
Gartneriet - http://www.gartneriet.dk/

On Mon, 22 Aug 2011 08:10:28 +0200, kalle@php.net (Kalle Sommer Nielsen)
wrote:

After upgrading to php 5.3.7, whenever I use is_a($object, 'ClassName');
the autoloader of classes is now called.

This did not happen in earlier versions of php 5.3 that I used before.
But I cannot find any  mention of it anywhere, no open bugs for it, and
nothing in the changelogs.

Is it a bug or is it intentional that it has started behaving this way?

I'm unable to reproduce your case in 5.3.4RC1, 5.3.7 and 5.3-svn:
http://pastie.org/2410070

Ah, I now see that it only happens when trying to check something which
is not actually an object:

<?php

function __autoload($class) {
       echo "Would load: " . $class . PHP_EOL;
}

$var = "test";
var_dump(is_a($var, 'B'));

$obj = new Stdclass;
var_dump(is_a($obj, 'C'));

?>

But still, it did not happen in earlier phpversions.

I can reproduce that in 5.3-svn and 5.4-svn.

Please file a bug report for it, this should probably be fixed in 5.3.8 too.

-Hannes

Hi,

On Mon, 22 Aug 2011 08:10:28 +0200, kalle@php.net (Kalle Sommer Nielsen)
wrote:

After upgrading to php 5.3.7, whenever I use is_a($object, 'ClassName');
the autoloader of classes is now called.

This did not happen in earlier versions of php 5.3 that I used before.
But I cannot find any  mention of it anywhere, no open bugs for it, and
nothing in the changelogs.

Is it a bug or is it intentional that it has started behaving this way?

I'm unable to reproduce your case in 5.3.4RC1, 5.3.7 and 5.3-svn:
http://pastie.org/2410070

Ah, I now see that it only happens when trying to check something which
is not actually an object:

<?php

function __autoload($class) {
       echo "Would load: " . $class . PHP_EOL;
}

$var = "test";
var_dump(is_a($var, 'B'));

$obj = new Stdclass;
var_dump(is_a($obj, 'C'));

?>

But still, it did not happen in earlier phpversions.
Here is the situation:

1. The underlying implementation is shared between is_a and is_subclass_of.
2. Previously, strings as first argument was not permitted by is_a but
   was for is_subclass_of,
3. is_subclass_of always triggered autoload in such cases.
4. Following a fix from Dmitry, the underlying implementation now
   allows a string as first argument for is_a as well.

Conclusion: it is now consistent, but if you wrongly used is_a with a
string before, it now triggers autoload because it actually accepts
it.

Best,

--
Mads Lie Jensen - mads@gartneriet.dk - ICQ #25478403
Gartneriet - http://www.gartneriet.dk/

--

--
Etienne Kneuss
http://www.colder.ch

Hi!

Ah, I now see that it only happens when trying to check something which
is not actually an object:

<?php

function __autoload($class) {
echo "Would load: " . $class . PHP_EOL;
}

$var = "test";
var_dump(is_a($var, 'B'));

$obj = new Stdclass;
var_dump(is_a($obj, 'C'));

?>

Not a bug. $var is interpreted as a class name. To know if one class
extends another, the class in question (first one) should be loaded.
There's no need to load the second one since if it's unknown nothing can
be instance of it and existing classes can not extend it.

Stanislav Malyshev, Software Architect
SugarCRM: http://www.sugarcrm.com/
(408)454-6900 ext. 227