Bug #824

Assignment to $this

Details

Submitted	2004-02-21 21:09 UTC
From	pear-qa at lists dot php dot net
Status	Duplicate
Package	Net_DNS
PHP Version	5.0.0b4 (beta4)
OS	Irrelevant
Roadmaps	(Not assigned)

Comments

[2004-02-21 21:09 UTC] pear-qa at lists dot php dot net

Description:
------------
## from the PEAR QA team ##
## quality-assurance related ##
## PHP 5 compatibility issue ##

Dear package maintainer,

your package makes use of the assignement of new values to $this. This methodis possible in PHP 4 but will throw an error with PHP 5 [1]. Please take care of this issue forPHP5 compatibility reasons.

Please answer to this bugreport directly through the PEAR bug tracker or the mailinglist pear-qa@lists.php.net .

With kind regards,
PEAR QA Team

[1] http://www.php.net/ChangeLog-5.php#5.0.0b4

Reproduce code:
---------------
Affected are constructs like:

FILE: '/php/pear/Net_DNS/DNS/RR.php' :
/php/pear/Net_DNS/DNS/RR.php(65): $this = $this->new_from_string($rrdata);
/php/pear/Net_DNS/DNS/RR.php(68): $this = $this->new_from_data($name, $rrtype, $rrclass, $ttl, $rdlength, $data, $offset);
/php/pear/Net_DNS/DNS/RR.php(70): $this = $this->new_from_array($rrdata);

Expected result:
----------------
Solutions:

The assignment to $this occurs mostly inside constructors (<Your_Package_Name>()). You should provide an static factory() or singleton() method for this.

To provide backwards compatibility you should work around the affected code pieces. This can be done by a version check:

if (version_compare(phpversion(), "5.0.0") == -1) {
// assign factoried method to this for PHP 4
// $this =& <Your_Package_Name>::factory();
$this =& <Your_Package_Name>::singleton();
} else {
// error handling for PHP5
// user has to use the factory()/singleton() method
}