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Bug #27059 Variable with empty name can be made
Submitted: 2004-01-27 10:17 UTC Modified: 2004-01-29 09:57 UTC
Votes:1
Avg. Score:5.0 ± 0.0
Reproduced:0 of 0 (0.0%)
From: uno at venus dot dti dot ne dot jp Assigned:
Status: Wont fix Package: Scripting Engine problem
PHP Version: 4CVS, 5CVS OS: *
Private report: No CVE-ID: None
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 [2004-01-27 10:17 UTC] uno at venus dot dti dot ne dot jp 
Description:
------------
Variable or object property can be made with empty name.
This behaviour doesn't match the manual.

http://www.php.net/manual/en/language.variables.php
Variable names follow the same rules as other labels in PHP.
A valid variable name starts with a letter or underscore,
followed by any number of letters, numbers, or underscores.
As a regular expression, it would be expressed thus:
'[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*' 

http://www.php.net/manual/en/language.oop.php
A class is a collection of variables and functions working
with these variables.


Reproduce code:
---------------
<?php
error_reporting(E_ALL);

${''} = 'abc';
echo ${''};

class X{
}
$x = new X;
$x->{''} = 'def';
echo $x->{''};
?>


Expected result:
----------------
Error. (warning or notice are acceptable for me)


Actual result:
--------------
abcdef

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 [2004-01-28 21:37 UTC] iliaa@php.net 
It would be too slow to add checks for the various strange 
things you can do inside {}, simply because these checks 
would need to occur realtime vs script parsing time.
 [2004-01-29 00:00 UTC] uno at venus dot dti dot ne dot jp 
Fmm...
When you read ${''} (or $x->{''}) without assigning, PHP notices 'Undefeined variable(property): in ...' on current implementation. So I suppose that checks need to be added only when assiging new dynamic variable and performance problem may be not too heavy.
 [2004-01-29 09:13 UTC] moriyoshi@php.net 
No matter how much it would slow down the exection, I 
think we ought to maintain the backwards compatibility 
as I know there are several scripts that depend on the 
behaviour.
 [2004-01-29 09:57 UTC] uno at venus dot dti dot ne dot jp 
Sure. I understand backward compatibility is important. Accuracy of language specification also.
If development team take this behaviour not a bug, I suppose that definition of variable name in the manual needs a little more clarification.
 
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