Re: [off] PHP: a fractal of bad design
| From: | Hartmut Holzgraefe | Date: | Mon, 07 May 2012 12:38:01 +0000 |
| Subject: | Re: [off] PHP: a fractal of bad design | ||
| References: | 1 2 3 4 5 6 | Groups: | php.internals |
| Request: | Send a blank email to internals+get-60509@lists.php.net to get a copy of this message | ||
On 05/07/2012 05:32 AM, Tjerk Anne Meesters wrote:
> Validated or not, why would type juggling even come into the picture
> if both variables are of the same type?
For the simple reason that web forms return all input as strings, even
if the input is actually meant to be numeric
Many PHP database backend functions also return all result fields
as strings regardless of the actual result type, e.g. mysql_fetch_*(),
mysqli_fetch_*() and pg_fetch_*() (although that's more debatable)
So if both operands look numeric (even though they are actually of
type string) type juggling kicks, and in your MD5 example it
unfortunately kicks in with a conversion to float for both sides
and you're running into the "never compare floats for equality"
trap ... (which is being worked on for the string comparison case
though, i just don't have the bug number at hand right now)
--
hartmut