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Bug #45400 $foo = $foo does not work in some cases
Submitted: 2008-07-01 11:34 UTC Modified: 2008-07-01 13:00 UTC
From: php at darkk dot net dot ru Assigned:
Status: Not a bug Package: Scripting Engine problem
PHP Version: 5.2.6 OS: Linux, FreeBSD
Private report: No CVE-ID: None
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 [2008-07-01 11:34 UTC] php at darkk dot net dot ru 
Description:
------------
Converting from string to array using
$name['foobar'] = $name
does not work in some cases.

Reproduce code:
---------------
first:

function foobar($name) {
  $name['anything'] = $name; 
  var_dump($name); 
}
foobar("foobar");'


second:

$name = "foobar";
$name['anything'] = $name;
var_dump($name);

Expected result:
----------------
in both cases I expect to see:
array(1) {
  ["anything"]=>
  string(6) "foobar"
}


Actual result:
--------------
first:
string(6) "oobar"

second:
string(6) "foobar"

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 [2008-07-01 11:43 UTC] php at darkk dot net dot ru 
I've just found workaround for both issues:
- $name['anything'] = $name;
+ $name = array('anything' => $name);

I also can say that 5.2.0 and 5.2.3 are not affected (at least that's what people at #php @ freenode say).
 [2008-07-01 12:49 UTC] johannes@php.net 
In your code:

$name = "foobar";
$name['anything'] = $name;


$name['anything'] is addressing a string offset, 'anything' is casted to 0 so you're overwriting the first character of $name with $name.

The first result, string(6) "oobar", is looking like it's overwriting the first byte with a null byte, which isn't what one expects but related to the way PHP optimizes access to variables, which isn't made for "wrong" code.
 [2008-07-01 13:00 UTC] php at darkk dot net dot ru 
Thank you. I know, that test-case is weird.

I was sure it was some sort of "undefined behavior", but I saw no warnings/notices and I got two different(sic!) results for same code, so I posted the bug.
 
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