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Bug #68162 isset($$varname) always true
Submitted: 2014-10-06 04:51 UTC Modified: -
From: pegasus at vaultwiki dot org Assigned:
Status: Closed Package: Scripting Engine problem
PHP Version: master-Git-2014-10-06 (Git) OS: Centos 6 64-bit
Private report: No CVE-ID: None
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From: pegasus at vaultwiki dot org
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 [2014-10-06 04:51 UTC] pegasus at vaultwiki dot org
Description:
------------
It seems that isset (likely others like unset, empty, etc) cannot properly resolve variably-named variables and simply returns true.

Test script:
---------------
function testWrapper()
{
	foreach (array(
		'testvar1',
		'testvar2'
	) AS $varname)
	{
		if (!isset($$varname))
		{
			echo "\nSetting $varname\n";
			$$varname = array();
		}

		var_dump($$varname);
	}
}

testWrapper();

Expected result:
----------------
Setting testvar1
array(0) {}
Setting testvar2
array(0) {}

Actual result:
--------------
NULL
NULL

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 [2014-10-06 17:03 UTC] nikic@php.net
I can't repro this.
 [2014-10-06 18:01 UTC] pegasus at vaultwiki dot org
Strange. I thought I was going crazy for a bit, then I tried messing around with actually trying to use the arrays created by the test. The testWrapper above indeed works normally on its own, but add the following immediately after the foreach loop in testWrapper:

####
$testvar1 = array_merge($testvar1, array());
$testvar2[] = true;
####
 [2014-10-06 18:39 UTC] nikic@php.net
Automatic comment on behalf of nikic
Revision: http://git.php.net/?p=php-src.git;a=commit;h=e24c24c1087c6405e842fdd7afcd84b224eb75bf
Log: Fix bug #68162: isset($$varname) always true
 [2014-10-06 18:39 UTC] nikic@php.net
-Status: Open +Status: Closed
 [2014-10-07 07:10 UTC] ab@php.net
Automatic comment on behalf of nikic
Revision: http://git.php.net/?p=php-src.git;a=commit;h=e24c24c1087c6405e842fdd7afcd84b224eb75bf
Log: Fix bug #68162: isset($$varname) always true
 [2016-07-20 11:40 UTC] davey@php.net
Automatic comment on behalf of nikic
Revision: http://git.php.net/?p=php-src.git;a=commit;h=e24c24c1087c6405e842fdd7afcd84b224eb75bf
Log: Fix bug #68162: isset($$varname) always true
 
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