From:
Operating system: Linux, Redhat Enterprise
PHP version: 5.3.5
Package: Arrays related
Bug Type: Bug
Bug description:isset() and empty() produce apparently spurious runtime error
Description:
------------
First, apologies, this is 5.3.3. I have no means of upgrading to check
whether
this is a fixed issue. I can't see anything similar in the bug database.
An expression of the form
isset($obj->m['a']['b'])
produces a runtime error when m is not actually an array but a zero length
string:
Uninitialized string offset: 0
The same is the case if I use empty instead of isset.
The same code worked in 5.2. Changing it to
isset($obj->m['a']) && isset($obj->m['a']['b'])
works.
isset is not supposed to produce any runtime error, surely, in this kind of
use.
The object member values arise from a database lookup, and normally the
field (m
above) will be a serialized array in the database, but the first time the
database column will be empty, leading to an empty string assignment to m.
In
addition once populated the object is stored in $_SESSION (actually in
$_SESSION['p']['q']) and then $obj is obtained by assignment from the
session,
like this
$session =& $_SESSION['p']; // where $_SESSION['p'] is set in a previous
page
// populate new $obj1 from database
$session['q'] = $obj1;
...
$obj =& $session['q'];
and the offending code is then executed elsewhere some time later.
However, abstracting the code from this much bigger program does not
demonstrate
the problem, which suggests to me something is corrupted somewhere. This is
what
I tried on its own, which is as close as I can reasonably get to the
situation
here, but it works. (The =& are leftovers from what was originally a PHP4
app; I
know all objects are assigned by reference in PHP5).
class c { var $m; }
session_start();
if (! isset($_SESSION['p'])) {
$_SESSION['p'] = array();
echo "set session array";
exit;
}
$session =& $_SESSION['p'];
$obj1 = new c();
$obj1->m = '';
$session['q'] = $obj1;
$obj =& $session['q'];
function check() {
global $obj;
echo (isset($obj->m['a']['b']) ? 'Yes' : 'No');
}
check();
Expected result:
----------------
isset to return FALSE
Actual result:
--------------
runtime error
Uninitialized string offset: 0
--
Edit bug report at http://bugs.php.net/bug.php?id=53971&edit=1
--
Try a snapshot (PHP 5.2):
http://bugs.php.net/fix.php?id=53971&r=trysnapshot52
Try a snapshot (PHP 5.3):
http://bugs.php.net/fix.php?id=53971&r=trysnapshot53
Try a snapshot (trunk):
http://bugs.php.net/fix.php?id=53971&r=trysnapshottrunk
Fixed in SVN:
http://bugs.php.net/fix.php?id=53971&r=fixed
Fixed in SVN and need be documented:
http://bugs.php.net/fix.php?id=53971&r=needdocs
Fixed in release:
http://bugs.php.net/fix.php?id=53971&r=alreadyfixed
Need backtrace:
http://bugs.php.net/fix.php?id=53971&r=needtrace
Need Reproduce Script:
http://bugs.php.net/fix.php?id=53971&r=needscript
Try newer version:
http://bugs.php.net/fix.php?id=53971&r=oldversion
Not developer issue:
http://bugs.php.net/fix.php?id=53971&r=support
Expected behavior:
http://bugs.php.net/fix.php?id=53971&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=53971&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=53971&r=submittedtwice
register_globals:
http://bugs.php.net/fix.php?id=53971&r=globals
PHP 4 support discontinued: http://bugs.php.net/fix.php?id=53971&r=php4
Daylight Savings: http://bugs.php.net/fix.php?id=53971&r=dst
IIS Stability:
http://bugs.php.net/fix.php?id=53971&r=isapi
Install GNU Sed:
http://bugs.php.net/fix.php?id=53971&r=gnused
Floating point limitations:
http://bugs.php.net/fix.php?id=53971&r=float
No Zend Extensions:
http://bugs.php.net/fix.php?id=53971&r=nozend
MySQL Configuration Error:
http://bugs.php.net/fix.php?id=53971&r=mysqlcfg
