ID: 25566
User updated by: Jared dot Williams1 at ntlworld dot com
-Summary: switch expressions seem to get cast to specific type.
Reported By: Jared dot Williams1 at ntlworld dot com
Status: Open
Bug Type: Scripting Engine problem
PHP Version: 4.3.3
New Comment:
Changed Summary to reflect more general problem.
Previous Comments:
------------------------------------------------------------------------
[2003-09-20 06:20:46] Jared dot Williams1 at ntlworld dot com
How's this for an impossibility..
echo('a' != 0 ? 'TRUE' : 'FALSE');
echo('<br />');
echo('a' ? 'TRUE' : 'FALSE');
Outputs:
FALSE
TRUE
------------------------------------------------------------------------
[2003-09-20 06:08:53] Jared dot Williams1 at ntlworld dot com
Oh erm, seems its not limited to switch either. :/
echo('a' == 0 ? 'YES' : 'NO');
Outputs: YES
echo('3a' == 3 ? 'YES' : 'NO');
Outputs: YES
echo(4 == '4a' ? 'YES' : 'NO');
Outputs: YES
Surely these cant be considered equivalent.
------------------------------------------------------------------------
[2003-09-20 05:51:09] Jared dot Williams1 at ntlworld dot com
The non-numeric string values are getting cast to integer value 0,
which then match case 0:.
$t = array(10,1,2,3,'*','+','3a', 'b');
foreach($t as $v)
switch ($v)
{
case 10: echo('0'); break;
case 1: echo('1'); break;
case 2: echo('2'); break;
case 3: echo('3'); break;
case '*': echo('*'); break;
default: echo($v); break;
}
Outputs:
0123*+3b
as 3a gets cast to 3. so seems there is a missing a condition in the
code somewhere, to see if the switched expression can actually be a
numeric type.
Also
$t = array(10,1,2,3,'*','+','3a', 'b');
foreach($t as $v)
switch ($v)
{
case 10: echo('0'); break;
case 1: echo('1'); break;
case 2: echo('2'); break;
case '*': echo('*'); break;
case '3a': echo('!!'); break;
default: echo($v); break;
}
?>
Outputs:
012!!*+!!b
So the case labels are getting cast too without the check.
------------------------------------------------------------------------
[2003-09-20 00:40:40] shadowfaxx at cc dot com
To add to the above, it seems that the '0' case is the culprit. If you
use the code below where '10' replaces '0', the weird behavior does not
occur:
$t = array(10,1,2,3,'*','+','a', 'b');
foreach($t as $v)
switch ($v)
{
case 10: echo('0'); break;
case 1: echo('1'); break;
case 2: echo('2'); break;
case 3: echo('3'); break;
case '*': echo('*'); break;
default: echo($v); break;
}
OutPut: 0123*+ab
So it seems that Case 0: grabs all the cases which are of a different
data type if the case expressions are not of the same type i.e. numeric
and string.
------------------------------------------------------------------------
[2003-09-16 18:47:44] Jared dot Williams1 at ntlworld dot com
"The first 5 array" should read "The first 4 array"
------------------------------------------------------------------------
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/25566
--
Edit this bug report at http://bugs.php.net/?id=25566&edit=1
