Re: [PHP-PEAR] DB_mysql Bugs?

Quoting Vinai Kopp <[email protected]>:

> 1.) This one is close to the preceding one. The way I see it a bug was
> introduced in Revision 1.44 of DB.php.
> The function isError now returns true if NULL is passed as an argument.
> That way it's not possible to do 
>       if( DB::isError( $var ) ) print $var->getMessage();
> anymore without doing another is_object or something first. Also, it
> would make it impossible to return NULL if no more data can be fetched
> from a query in fetchRow and similar functions. I suggest to change it
> back.

Okay, I'll elaborate a bit more on this. I changed DB::isError() to flag NULL 
as an error because some of the db backends were returning NULL at the end of a 
result set, and some were returning an error object. If you want to be able to 
write a while loop that will terminate on an error or at the end of a result 
set, you need a single check that will tell you if either occurred.

If we could make objects evaluate to false, then we could make DB_error objects 
evaluate to false and we'd have a simple check. If we had exceptions, we could 
throw an exception and just check for null, and we'd have a simple check. But 
as it is, you'd need:

$row = $result->fetchRow();
while (($row != null) && !DB::isError($row)) {
    // stuff
    $row = $result->fetchRow();
}

... if you wanted null at the end of a result set (I agree that this makes the 
most sense, yes), and DB::isError didn't consider null an error.

To me, that's an awkward thing to force people to do. Maybe all this could be 
solved by a new function: DB::isResult().

while (DB::isResult($row = $result->fetchRow())) {
    // stuff
}
if (DB::isError($row)) {
    // error
}

You still need a second check to see if you have an error - but without 
exceptions, there's no way around that.

-chuck

--
Charles Hagenbuch, <[email protected]>
"My intuitive grasp of math often leads me astray." -Me