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! 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.