Edit report at https://bugs.php.net/bug.php?id=62680&edit=1
ID: 62680
Comment by: kriscr...@php.net
Reported by: kriscr...@php.net
Summary: Function isset() throws fatal error on set array if
non-existent key depth >= 3
Status: Open
Type: Bug
Package: Arrays related
Operating System: Linux and Windows
PHP Version: 5.3.15
Block user comment: N
Private report: N
New Comment:
I'm still fairly new to the codebase compared to most of you karma folks, so if
this looks like something a relative newbie could handle, please point me in
the right direction and I'd be happy to just assign this one to myself. It'll
probably take way longer but I imagine it would be a good learning experience
for me if I had a little guidance to get me started.
Thanks! =)
Previous Comments:
------------------------------------------------------------------------
[2012-07-27 23:01:29] kriscr...@php.net
Description:
------------
The test script sums it up pretty well. Basically, if I pass an array with a
missing key to isset(), it's not supposed to throw an error. After all,
isset() is generally what people use for those kinds of sanity checks where
unexpected data might be returned.
However, I just noticed (completely by accident) that, if you're passing an
array with a set key followed by three or more missing keys to isset(), PHP
will throw a fatal error and script execution will terminate at that point.
What's particularly strange about this is that it only seems to occur if the
top-level array variable AND its first key are both set. If I use the same
depth on an undefined variable or on the defined array but with the top-level
key being undefined, it works just fine.
In the example, this would mean that $non_existent_variable[...][...][...][...]
is fine and $arr[0][...][...][...] is fine ($arr is defined but $arr[0] and
$non_existent_variable are not). However, if I do $arr["key"][...][...][...],
where $arr["key"] is defined but the subsequent [...] keys are not, a fatal
error is thrown. That's clearly a bug.
In case anyone else encounters this before it's fixed, you can work around it
by adding some additional (albeit cluttery) sanity checks. For example, if
your $arr["key"] is not an array and that's causing the error, simply add
is_array( $arr["key"] ) to the ifcheck prior to isset and that will allow your
script to proceed without dying.
I've already created a PHPT case for this. It'd probably be a good idea to add
it to run_tests, though I'm not entirely certain how/where to do that.
Looks like this bug was previously documented in 5.2.x
(https://bugs.php.net/bug.php?id=44431), but it was closed with a comment
saying that it had been fixed (or at least couldn't be repro'd) in 5.2.6. So
I'm guess either that person wasn't properly reproducing the conditions of the
bug somehow or this is a regression.
Tested on Windows 7 x86_64 and CentOS 5.8 x86_64. In both cases, PHP version
was 5.3.15 (VC9 ZTS build on Windows). Tested both via Apache/mod_php and CLI.
I have not tested this on 5.4 yet. I don't have a 5.4 environment handy at
the moment, so if somebody else could repro this on that version I'd be much
obliged. Thanks!
Test script:
---------------
<?php
$arr = array( "key" => "",
"key2" => array( "subkey" => array( "supersubkey" => array(
"superdupersubkey" => "Hello." ) ) ),
"key3" => array( "subkey" => array( "supersubkey" => "Hello." )
) );
if ( isset( $arr["key"]["non_existant_key"] ) )
{
print "Arroooo?";
}
print "DEBUG #1.<br />\r\n";
$out = ( isset( $arr["key"]["non_existant_key"] ) ? "WTF?!" : NULL );
print "DEBUG #2.<br />\r\n";
foreach ( $arr as $key => $row )
{
print ( isset( $row["subkey"]["supersubkey"] ) ?
$row["subkey"]["supersubkey"] . "<br />\r\n" : NULL );
}
print "DEBUG #3.<br />\r\n";
if ( isset( $arr[0]["subkey"]["supersubkey"]["superdupersubkey"] ) )
{
die( "Error : T_PAAMAYIM_NEKUDOTAYIM is too hard to pronounce!" );
}
print ( isset( $arr[0]["subkey"]["supersubkey"]["superdupersubkey"] ) ?
"BAD-0<br />\r\n" : "OK-0<br />\r\n" );
print ( isset( $arr["key"]["subkey"]["supersubkey"]["superdupersubkey"] ) ?
"BAD-1<br />\r\n" : "OK-1<br />\r\n" );
print ( isset( $arr["key2"]["subkey"]["supersubkey"]["superdupersubkey"] ) ?
"OK-2<br />\r\n" : "BAD-2<br />\r\n" );
print ( isset( $arr["key3"]["subkey"]["supersubkey"]["superdupersubkey"] ) ?
"BAD-3<br />\r\n" : "OK-3<br />\r\n" );
print "DEBUG #4.<br />\r\n";
foreach ( $arr as $key => $row )
{
print ( isset( $row["subkey"]["supersubkey"]["superdupersubkey"] ) ?
$row["subkey"]["supersubkey"]["superdupersubkey"] . "<br />\r\n" : NULL );
}
print "DEBUG #5.";
?>
Expected result:
----------------
DEBUG #1.<br />
DEBUG #2.<br />
Array<br />
Hello.<br />
DEBUG #3.<br />
OK<br />
OK-0<br />
OK-1<br />
OK-2<br />
OK-3<br />
DEBUG #4.<br />
Hello.<br />
DEBUG #5.
Actual result:
--------------
DEBUG #1.<br />
DEBUG #2.<br />
Array<br />
Hello.<br />
DEBUG #3.<br />
OK<br />
OK-0<br />
<br />
<b>Fatal error</b>: Cannot use string offset as an array in <b>C:\Program
Files (x86)\Apache2.2\htdocs\test8.php</b> on line <b>28</b><br />
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Edit this bug report at https://bugs.php.net/bug.php?id=62680&edit=1
