> -----Original Message-----
> From: Gary [mailto:php-gene...@garydjones.name]
> Sent: Tuesday, October 19, 2010 11:38 PM
> To: php-general@lists.php.net
> Subject: [PHP] Re: Possible foreach bug; seeking advice to isolate the
> problem
>
> Jonathan Sachs wrote:
> > I've got a script which originally contained the following piece of
> > code:
> >
> > foreach ( $objs as $obj ) {
> > do_some_stuff($obj);
> > }
> >
> > When I tested it, I found that on every iteration of the loop the last
> > element of $objs was assigned the value of the current element.
>
> I only had a few minutes to look at it, but here is my 2 Euro cents.
>
> It only occurs when you have previously done
> ,----
> | foreach ( $objs as &$obj ) {
> | //anything or nothing here
> | }
> `----
> as described in the documentation.
>
> > That leaves me with the question: what is going wrong with foreach?
> > I'm trying to either demonstrate that it's my error, not the PHP
> > engine's, or isolate the problem in a small script that I can submit
> > with a bug report.
>
> From the post you reference in the manual's comments:
> $a = array('a', 'b','c');
> foreach($a as &$row){
> //you don't have to do anything here
> }
> print_r($a);
> foreach($a as $row){
> echo "<br />".$row;
> }
> print_r($a);
>
> This suffices.
>
> > I tried to eliminate the database by doing a var_export of the array
> > after I built it, then assigning the exported expression to a variable
> > immediately before the foreach. That "broke the bug" -- the loop
> > behaved correctly.
>
> Yup. I guess whatever database code used previously was doing the
> equivalent of the first foreach in the previous code snippet.
>
> > Can anyone make suggestions on this -- either insights into what's
> > wrong, or suggestions for producing a portable, reproducible example?
>
> Better. I can tell you how to solve it:
> $a = array('a', 'b','c');
> foreach($a as &$row){
> //you don't have to do anything here
> }
> unset($row); // <----<<< THIS IS KEY!
Shouldn't that be $row = null since unset will remove the last value, not
just removing the variable also, from the array whereas the $row = null will
tell the reference pointer that it doesn't point to a value.
> print_r($a);
> foreach($a as $row){
> echo "<br />".$row;
> }
> print_r($a);
>
> I admit though, it's not obvious, even from reading the manual, and is
> definitely a bug in the sense it is unexpected behaviour. Documenting it
> and calling it a "feature" is appalling.
>
Regards,
Tommy
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