Doc #44821 [Nab->Csd]: Accessing NULL as an Array does not produce error
| From: | cmb@php.net | Date: | Fri, 30 Dec 2016 16:00:30 +0000 |
| Subject: | Doc #44821 [Nab->Csd]: Accessing NULL as an Array does not produce error | ||
| References: | 1 | Groups: | php.doc.bugs |
| Request: | Send a blank email to doc-bugs+get-14300@lists.php.net to get a copy of this message | ||
Edit report at https://bugs.php.net/bug.php?id=44821&edit=1
ID: 44821
Updated by: cmb@php.net
Reported by: mcarpent at zenwerx dot com
Summary: Accessing NULL as an Array does not produce error
-Status: Not a bug
+Status: Closed
Type: Documentation Problem
-Package: Documentation problem
+Package: Arrays related
Operating System: Windows XP
PHP Version: 5.2.5
-Assigned To:
+Assigned To: cmb
Block user comment: N
Private report: N
New Comment:
This behavior has been documented in the meantime, see
<http://svn.php.net/viewvc?view=revision&revision=339937>.
Note that there's request #37676, which is about changing this
behavior.
Previous Comments:
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[2013-08-21 23:59:11] matteosistisette at gmail dot com
Forgot to mention: NEEDS TO BE REOPENED
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[2013-08-21 23:58:02] matteosistisette at gmail dot com
"It is properly documented: "Converting NULL to an array results in an
empty"."
THAT's WRONG!!
And both the original report and the first comment already point this out.
Accessing a non-existing key of an empty array produces an E_NOTICE,
Hence, if you try to access a key of null, and null was converted to an empty
array, you would be accessing an element of an empty array, and hence you should
get an E_NOTICE. But you don't.
This IS a bug. Or a documentation problem if there is a good reason (which I
cannot see) for such an absurd behavior.
It is definitely not as documented.
Compare these:
$arr=array();
echo $arr['lsjsdfjls']; // issues an E_NOTICE
$arrb=null;
echo $arrb['losjfbls']; // doesn't issue an E_NOTICE
This made me waste a day debugging.
------------------------------------------------------------------------
[2008-11-05 17:02:26] vrana@php.net
It is properly documented: "Converting NULL to an array results in an empty".
------------------------------------------------------------------------
[2008-04-24 17:14:35] mcarpent at zenwerx dot com
The string example was only used for testing after I found this particular issue.
Real code was more like this:
function returnNull() {
return NULL;
}
$foo = returnNull();
// Resolves to null, therefore always false
if ($foo['SomeIndex'] == 1) {
// Never reached
}
This was a programmer error since it should have been checked for failure (null), but was left
uncaught until the code was changed so that the function, which should return an array, returned an
empty array instead of null to signify failure.
If this is behaviour by design, it would be helpful for the documentation about silently casting the
object to null to be located elsewhere as well. I would have never considered looking under the
string documentation for an array issue.
------------------------------------------------------------------------
[2008-04-24 16:59:00] florian dot ember at gmail dot com
http://php.net/language.types.string#language.types.string.substr
"Note: Accessing variables of other types using [] or {} silently returns NULL."
Typecasting only happens when you explicitly do it with (array).
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the rest of the comments, please view the bug report online at
https://bugs.php.net/bug.php?id=44821
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