Edit report at http://bugs.php.net/bug.php?id=42780&edit=1
ID: 42780
Comment by: rowan dot collins at gmail dot com
Reported by: lordi at msdi dot ca
Summary: Invalid type casting ?
Status: Wont fix
Type: Bug
Package: SimpleXML related
Operating System: Freebsd + windows
PHP Version: 5.2.4
Assigned To: rrichards
Block user comment: N
New Comment:
Hi,
I was about to report this bug myself, and am surprised at the
resolution, as this seems to be very unhelpful and unexpected
behaviour.
Consider the following minimal test case:
<?php
$x = simplexml_load_string('<x>2.5</x>');
var_dump($x*1); // int(2)
var_dump((string)$x*1) // float(2.5)
?>
Is there any other value of $x that would create the behaviour shown
with those 2 var_dump() calls?
You say that "when performing mathematical operations on objects, they
are treated as integers", but I'm not aware of any other object which
interprets its contents to cast to integer in this way. Certainly any
user-defined class will simply become int(1) in this context, so
SimpleXML is *attempting* to perform extra "magical" functionality
here.
I discovered this in a production application which was dropping pennies
from prices returned in XML by a supplier - a non-trivial bug. If the
implicit cast had resulted in int(1), like any other object, this would
have been ridiculously obvious; but since SimpleXML('<x>42.0</x>')
appears to act as float(42.0), there was no reason to suspect that
SimpleXML('<x>42.5</x>') would not act as float(42.5).
I also note that if $x in the example were the string '2.5',
var_dump($x*1) would result in float(2.5) as expected, so it is not true
that the engine has already decided that the variable is in int
context.
If this is a limitation of the engine, then that should be raised as a
dependency of fixing this bug, not used as an excuse to dismiss it.
Many thanks for all your efforts,
Rowan Collins
Previous Comments:
------------------------------------------------------------------------
[2007-10-23 11:35:08] rricha...@php.net
The behavior is defined by the engine not the extension. When performing
mathematical operations on objects, they are treated as integers. It is
up to the user to cast the object to the appropriate type to maintain
proper precision.
------------------------------------------------------------------------
[2007-09-27 16:51:25] lordi at msdi dot ca
Description:
------------
Calculations on values got from a simplexml object dont work as
expected.
String values looking as float seems to be casted as integers
Reproduce code:
---------------
<?php
$objXML = new SimpleXMLElement('<test x="-123.45"></test>');
//Shows correctly
echo $objXML['x']."\n";
//We loose the decimals
echo $objXML['x'] + $objXML['x']."\n";
//This works if we cast the amounts
echo (float)$objXML['x'] + (float)$objXML['x']."\n";
//Calculated on a string, no problem
echo "-123.45" + "-123.45";
?>
Expected result:
----------------
-123.45
-246.9
-246.9
-246.9
Actual result:
--------------
-123.45
-246
-246.9
-246.9
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/bug.php?id=42780&edit=1
