#46600 [Com]: _empty_ key in objects (see #41504)
ID: 46600
Comment by: michaeldnelson dot mdn at gmail dot com
Reported By: Matt at mpcm dot com
Status: No Feedback
Bug Type: JSON related
Operating System: *
PHP Version: 5CVS, 6CVS (2008-11-18)
New Comment:
I am using freebsd 7.2 and php 5.2.10 the first test case
var_dump(json_decode('{:test}'));
silently stops processing of the script
The test case
var_dump(json_decode('{test2:5,:6}'));
Fatal error: Cannot access empty property
I am not sure the second is expected behavior but considering json is
often from feeds it would be nice to fail more gracefully.
Previous Comments:
[2008-12-26 01:00:01] php-bugs at lists dot php dot net
No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to Open.
[2008-12-23 16:47:05] matt at mpcm dot com
A note about this in the json_decode page would be appreciated. Perhaps
a strict mode flag, so that it can fail if it cannot be decoded as an
object (?). For the moment the only safe way to decode json is into
arrays.
The _empty_ behavior I thought was a bug (as it was with arrays) is a
required behavior for objects (at least without __get __set in a
wrapper class).
The bugs that jump out at me now can be seen with the code below... you
can create objects with unreachable properties. If that blank property
access is fixed, then this becomes not so much of an issue. Or it should
be stopped from ever happening... silent errors bite us all.
Illegal Member variable name if var_dump does it, fatal if a user does
it.
Notice: PHPDocument1 line 8 - Illegal member variable name
?
$blank = '';
$another = ' another';
$a = array($blank=1234, 'some other key'=5678, $another=);
$b = (object) $a;
$c = json_decode(json_encode($a));
var_dump($b);
var_dump($c);
#echo $b-$blank; //fatal
echo $b-$another; //works
#echo $c-$blank; //fatal
echo $c-$another; //works
?
[2008-12-18 03:27:25] scott...@php.net
I'm not even sure what the bug is? You can't have an empty property
name hence the use of _empty_.
The key collision thing is a very edge case, are you saying you ran
into this in a real life usage?
The best course of action may be to have this documented on the
json_encode() and json_decode() pages.
[2008-12-04 20:39:13] Matt at mpcm dot com
Thanx for the reply magicaltux, `Feature` is an interesting word
considering the possible key collision.
There are other ways to get things that are not strictly objects to
behave that way. Overloading (like example #1 at
http://us.php.net/manual/en/language.oop5.overloading.php). It works
well enough as long as you also make it iterate correctly.
What I am suggesting is that it is better to fail in decoding into an
object, than to silently cause a key collision.
Or alternatively, produce an overloaded object which can have these
keys (by default, or passed optional flag) from json_decode. It's an
opinion, but a wrapper gets me where I need to be for now, and I'm
pretty sure this is an edge case.
$a = '{:a,_empty_:b}';
echo json_encode(json_decode($a));
echo json_encode(json_decode($a, true));
output:
{_empty_:b}
{:a,_empty_:b}
for some values:
$a != json_encode(json_decode($a));
[2008-12-04 10:44:29] magical...@php.net
I believe this is not a bug, but a feature.
An object *can't* have an empty property (while an array can).
If you want to use json_decode() with json containing empty key, either
access those empty key using special keyword _empty_, or put the
optionnal $assoc parameter of json_decode() to true to get result as an
array.
If you want objects to support empty keys, I believe this is not going
to happen soon, as this is enforced by a specific error message.
Fatal error: Cannot access empty property in php shell code on line 1
Please note that a property name starting with NULL character won't
work either.
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
http://bugs.php.net/46600
--
Edit this bug report at http://bugs.php.net/?id=46600edit=1
#46600 [Com]: _empty_ key in objects (see #41504)
ID: 46600
Comment by: matt at mpcm dot com
Reported By: Matt at mpcm dot com
Status: Feedback
Bug Type: JSON related
Operating System: *
PHP Version: 5CVS, 6CVS (2008-11-18)
New Comment:
A note about this in the json_decode page would be appreciated. Perhaps
a strict mode flag, so that it can fail if it cannot be decoded as an
object (?). For the moment the only safe way to decode json is into
arrays.
The _empty_ behavior I thought was a bug (as it was with arrays) is a
required behavior for objects (at least without __get __set in a
wrapper class).
The bugs that jump out at me now can be seen with the code below... you
can create objects with unreachable properties. If that blank property
access is fixed, then this becomes not so much of an issue. Or it should
be stopped from ever happening... silent errors bite us all.
Illegal Member variable name if var_dump does it, fatal if a user does
it.
Notice: PHPDocument1 line 8 - Illegal member variable name
?
$blank = '';
$another = ' another';
$a = array($blank=1234, 'some other key'=5678, $another=);
$b = (object) $a;
$c = json_decode(json_encode($a));
var_dump($b);
var_dump($c);
#echo $b-$blank; //fatal
echo $b-$another; //works
#echo $c-$blank; //fatal
echo $c-$another; //works
?
Previous Comments:
[2008-12-18 03:27:25] scott...@php.net
I'm not even sure what the bug is? You can't have an empty property
name hence the use of _empty_.
The key collision thing is a very edge case, are you saying you ran
into this in a real life usage?
The best course of action may be to have this documented on the
json_encode() and json_decode() pages.
[2008-12-04 20:39:13] Matt at mpcm dot com
Thanx for the reply magicaltux, `Feature` is an interesting word
considering the possible key collision.
There are other ways to get things that are not strictly objects to
behave that way. Overloading (like example #1 at
http://us.php.net/manual/en/language.oop5.overloading.php). It works
well enough as long as you also make it iterate correctly.
What I am suggesting is that it is better to fail in decoding into an
object, than to silently cause a key collision.
Or alternatively, produce an overloaded object which can have these
keys (by default, or passed optional flag) from json_decode. It's an
opinion, but a wrapper gets me where I need to be for now, and I'm
pretty sure this is an edge case.
$a = '{:a,_empty_:b}';
echo json_encode(json_decode($a));
echo json_encode(json_decode($a, true));
output:
{_empty_:b}
{:a,_empty_:b}
for some values:
$a != json_encode(json_decode($a));
[2008-12-04 10:44:29] magical...@php.net
I believe this is not a bug, but a feature.
An object *can't* have an empty property (while an array can).
If you want to use json_decode() with json containing empty key, either
access those empty key using special keyword _empty_, or put the
optionnal $assoc parameter of json_decode() to true to get result as an
array.
If you want objects to support empty keys, I believe this is not going
to happen soon, as this is enforced by a specific error message.
Fatal error: Cannot access empty property in php shell code on line 1
Please note that a property name starting with NULL character won't
work either.
[2008-11-18 17:35:30] matt at mpcm dot com
The language seems to create a key that cannot be reached, so even if
this `bug` is fixed, we am still facing a broader issue it seems.
?
$key = ;
$o = (object) array($key=4,example=8);
var_dump($o);
print 'blank key test:' . (isset($o-$key)?'true':'false');
print $o-{$key};
var_dump($o-$key);
?
output:
object(stdClass)#1 (2) {
[]=
int(4)
[example]=
int(8)
}
blank key test:falsebr /
bFatal error/b: Cannot access empty property in
bPHPDocument1/b on line b8/bbr /
All throws Notice: line 4 - Illegal member variable name
[2008-11-18 15:43:05] matt at mpcm dot com
All the work arounds I am looking at are throwing Error Text: Illegal
member variable name when I convert/cast an object with a blank
property.
Is this json_decode `bug` a result of a larger object mechanism
limitation inside of php's object handling?
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
http://bugs.php.net/46600
--
Edit this bug report at http://bugs.php.net/?id=46600edit=1
#46600 [Com]: _empty_ key in objects (see #41504)
ID: 46600
Comment by: matt at mpcm dot com
Reported By: Matt at mpcm dot com
Status: Verified
Bug Type: JSON related
Operating System: *
PHP Version: 5CVS, 6CVS (2008-11-18)
New Comment:
All the work arounds I am looking at are throwing Error Text: Illegal
member variable name when I convert/cast an object with a blank
property.
Is this json_decode `bug` a result of a larger object mechanism
limitation inside of php's object handling?
Previous Comments:
[2008-11-18 03:13:51] Matt at mpcm dot com
Description:
json_decode() treats empty property name as _empty_ not . This was
fixed in #41504 for arrays, but not for objects. (seems to happen in PHP
Version 5.2.4-2ubuntu5.3 and 5.3.0alpha2.
Reproduce code:
---
?
$s = '{:test}';
var_dump(json_decode($s));
?
Expected result:
object(stdClass)#1 (1) { []= string(4) test }
Actual result:
--
object(stdClass)#2 (1) { [_empty_]= string(4) test }
--
Edit this bug report at http://bugs.php.net/?id=46600edit=1
#46600 [Com]: _empty_ key in objects (see #41504)
ID: 46600
Comment by: matt at mpcm dot com
Reported By: Matt at mpcm dot com
Status: Verified
Bug Type: JSON related
Operating System: *
PHP Version: 5CVS, 6CVS (2008-11-18)
New Comment:
The language seems to create a key that cannot be reached, so even if
this `bug` is fixed, we am still facing a broader issue it seems.
?
$key = ;
$o = (object) array($key=4,example=8);
var_dump($o);
print 'blank key test:' . (isset($o-$key)?'true':'false');
print $o-{$key};
var_dump($o-$key);
?
output:
object(stdClass)#1 (2) {
[]=
int(4)
[example]=
int(8)
}
blank key test:falsebr /
bFatal error/b: Cannot access empty property in
bPHPDocument1/b on line b8/bbr /
All throws Notice: line 4 - Illegal member variable name
Previous Comments:
[2008-11-18 15:43:05] matt at mpcm dot com
All the work arounds I am looking at are throwing Error Text: Illegal
member variable name when I convert/cast an object with a blank
property.
Is this json_decode `bug` a result of a larger object mechanism
limitation inside of php's object handling?
[2008-11-18 03:13:51] Matt at mpcm dot com
Description:
json_decode() treats empty property name as _empty_ not . This was
fixed in #41504 for arrays, but not for objects. (seems to happen in PHP
Version 5.2.4-2ubuntu5.3 and 5.3.0alpha2.
Reproduce code:
---
?
$s = '{:test}';
var_dump(json_decode($s));
?
Expected result:
object(stdClass)#1 (1) { []= string(4) test }
Actual result:
--
object(stdClass)#2 (1) { [_empty_]= string(4) test }
--
Edit this bug report at http://bugs.php.net/?id=46600edit=1
