PHP 4.0 Bug #8937 Updated: unset() in context with GLOBAL
| From: | derick@php.net | Date: | Fri, 26 Jan 2001 21:14:57 +0000 |
| Subject: | PHP 4.0 Bug #8937 Updated: unset() in context with GLOBAL | ||
| Groups: | php.dev | ||
| Request: | Send a blank email to php-dev+get-45100@lists.php.net to get a copy of this message | ||
ID: 8937
Updated by: derick
Reported By: aulbach@unter.franken.de
Old-Status: Open
Status: Closed
Bug Type: Scripting Engine problem
Assigned To:
Comments:
This isn't a bug, but a feature =)
If you use GLOBAL within a function it creates a reference to the orignal variabele, this reference
is local to the function. SO if you unset() this variabele, you're only unsetting the reference
(and thus not the GLOBAL variabele). This is documented behavior (from the unset() manual page):
If a globalized variable is unset() inside of a function, only the
local variable is destroyed. The variable in the calling environment
will retain the same value as before unset() was called.
Previous Comments:
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[2001-01-26 14:19:15] aulbach@unter.franken.de
The mentioned workarround (unset($GLOBALS['x'])) dosn't work with my testscript.
The result is exactly the same as with the first version of my script. I really have GREAT TROUBLES
to upgrade this old application to PHP4.
Result:
'/hugo/bla/fasel'
'/hugo/bla'
'/hugo'
DIR called with function test1(): Array ( [/hugo] => 1 [/hugo/bla] => 1 [/hugo/bla/fasel]
=> 1 )
'/hugo/bla/fasel'
'/hugo/bla'
'/hugo'
DIR called with function test2(): Array ( [/hugo/bla/fasel/test] => 1 [/hugo] => 1 [/hugo/bla]
=> 1 [/hugo/bla/fasel] => 1 )
Script:
<?
function test1 ($dir) {
GLOBAL $x;
unset($GLOBALS["x"]);
$x[$dir]=true;
mydirname($dir);
}
function test2 ($dir) {
GLOBAL $x;
####### unset($x); no unset!
$x[$dir]=true;
mydirname($dir);
}
function mydirname ($dir) {
GLOBAL $x;
$dir=ereg_Replace('/[^/]*$','',$dir);
if (!empty($dir)) {
echo "'$dir'<br>"; flush();
mydirname($dir);
$x[$dir]=true;
}
}
$dir="/hugo/bla/fasel/test"; # first char must be '/' !
unset($x);
test1($dir);
echo "DIR called with function test1(): "; print_r($x);
echo "<br>";
unset($x);
test2($dir);
echo "DIR called with function test2(): "; print_r($x);
?>
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[2001-01-26 14:05:26] aulbach@unter.franken.de
Of course I know that it is already documented. First mentioned in August 1999!
Havn't mentioned this, cause it is not relevant. A bug is bug, and the other tickets have been
closed, but the bug was remaining.
4 (or more?) other guys had the same trouble with this behaviour. How many others havn't
reported this bug? I know minimum 2 others, which havn't.
Sorry, but it IS a bug and a workarround is not a bugfix and my opinion is, that you make it too
easy for yourself to change the state of this ticket to "closed".
But I will not change it for you. I'll respect your decission.
---------------------------------------------------------------------------
[2001-01-26 11:54:16] jmoore@php.net
Thats thanks to Bjorn ;) Not my sig..
---------------------------------------------------------------------------
[2001-01-26 11:52:29] jmoore@php.net
Have a closer look at
http://bugs.php.net/bugs.php?id=1971
and the commentary of Zeev. You have to
use unset($GLOBALS["x"]);
--
Björn Schotte b.schotte@pangora.com
http://rent-a-phpwizard.de/ bjoern@baer.main.de
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[2001-01-26 10:25:19] aulbach@unter.franken.de
unset() in context with GLOBAL has a serious bug. This bug appeard,
when I changed a PHP3-program to PHP4. The problem is now,
that constructs like the following are several times in this old program.
Sorry, I haven't checked, if this problem is fixed in 4.0.4. If so, perhaps someone can tell
me? TIA.
Think this problem depends Zend, cause ZEND_CHANGES tells me:
"unset() is no longer a function, but a statement. It was never
documented as a function so the impact should be no bigger than nada."
I have made a test-case:
<?
function test1 ($dir) {
GLOBAL $x;
unset($x);
$x[$dir]=true;
mydirname($dir);
}
function test2 ($dir) {
GLOBAL $x;
####### unset($x); no unset!
$x[$dir]=true;
mydirname($dir);
}
function mydirname ($dir) {
GLOBAL $x;
$dir=ereg_Replace('/[^/]*$','',$dir);
if (!empty($dir)) {
echo "'$dir'<br>"; flush();
mydirname($dir);
$x[$dir]=true;
}
}
$dir="/hugo/bla/fasel/test"; # first char must be '/' !
unset($x);
test1($dir);
echo "DIRS called with function test1(): "; print_r($x);
echo "<br>";
unset($x);
test2($dir);
echo "DIRS called with function test2(): "; print_r($x);
?>
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Full Bug description available at: http://bugs.php.net/?id=8937