Edit report at http://bugs.php.net/bug.php?id=54131&edit=1
ID: 54131 Updated by: ras...@php.net Reported by: daniel-marschall at viathinksoft dot de Summary: _SERVER, _ENV access via $$ shows Notice -Status: Open +Status: Bogus Type: Bug Package: Unknown/Other Function Operating System: Debian PHP Version: 5.3.5 Block user comment: N Private report: N New Comment: This is not a bug. It is a documented optimization feature. See http://php.net/manual/en/ini.core.php and look for the section on auto_globals_jit with the big pink warning which says, "Usage of SERVER and ENV variables is checked during compile time so using them through e.g. variable variables will not cause their initialization." Previous Comments: ------------------------------------------------------------------------ [2011-03-02 05:09:42] daniel-marschall at viathinksoft dot de I have found something additional. (1) You can also "touch" the variable with simple <?php $_SERVER; ?> (2) You do not have to touch the Variable BEFORE you want to access it wit $$x. Actually, you just need to touch it ANYWHERE inside the script. Then, the PHP interpreter will "activate" $_SERVER. This scripts will throw an notice: <?php error_reporting(E_ALL | E_STRICT); $x = '_SERVER'; print_r($$x); ?> These scripts will not throw an notice <?php error_reporting(E_ALL | E_STRICT); print_r(${'_SERVER'}); ?> <?php error_reporting(E_ALL | E_STRICT); $x = '_SERVER'; print_r($$x); $_SERVER; // Touch anywhere in the script to avoid error ?> I believe the interpreter checks if $_SERVER or $_ENV is called somewhere in the script. If it is not called anywhere, it just don't load the variable. In my opinion, this behavior is wrong. Since PHP cannot know what I do with variables like $$x, it cannot know if I am actually trying to access $_SERVER or $_ENV . Solutions: (1) Always "enable" _SERVER and _ENV (2) When solving $$x , check if it is _SERVER or _ENV which is still disabled and then enable it. Then, access it. ------------------------------------------------------------------------ [2011-03-02 04:52:11] daniel-marschall at viathinksoft dot de Description: ------------ If you access $_ENV or $_SERVER the indirect way, via ${'_SERVER'} you get an E_NOTICE message. Please see my test scripts. Test script: --------------- Producing the bug: <?php error_reporting(E_ALL | E_STRICT); $x = '_SERVER'; print_r($$x); // Notice: Undefined variable: _SERVER ?> Workaround with dummy function which "touches" the variable: <?php error_reporting(E_ALL | E_STRICT); function dummy($dummy) {} dummy($_SERVER); // "Touch" $x = '_SERVER'; print_r($$x); // Everything is OK! ?> Expected result: ---------------- I don't expect an message that $_SERVER or $_ENV are not valid variables. I kept searching for hours because I couldn't find any reason, why $_SERVER disappears, but is visible in phpinfo(). I do not know why I have to "touch" these super- globals first, so that they get "active". ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/bug.php?id=54131&edit=1
