Doc #71458 [Com]: foreach docs should expand upon the references warning

Edit report at https://bugs.php.net/bug.php?id=71458&edit=1 ID: 71458 Comment by: cronfy at gmail dot com Reported by: requinix@php.net Summary: foreach docs should expand upon the references warning Status: Open Type: Documentation Problem Package: Scripting Engine problem PHP Version: Irrelevant Block user comment: N Private report: N New Comment: > Another option though would be to change behavior (in next major) and deref foreach () > references at the end of the loop... This can break existing code - reference to last array item may be expected. But is it possible to deref foreach $value at the START of foreach? I think it should work fine. Previous Comments: ------------------------------------------------------------------------ [2016-05-30 20:44:13] requinix@php.net Related To: Bug #72292 ------------------------------------------------------------------------ [2016-02-22 19:07:28] requinix@php.net Related To: Bug #71644 ------------------------------------------------------------------------ [2016-02-09 08:58:13] requinix@php.net Related To: Bug #71557 ------------------------------------------------------------------------ [2016-01-28 12:43:11] bwoebi@php.net Another option though would be to change behavior (in next major) and deref foreach () references at the end of the loop... ------------------------------------------------------------------------ [2016-01-26 19:51:38] requinix@php.net Description: ------------ Every other month there's a bug report about how having two foreach loops, the first with a reference and the second without, results in unexpected behavior. (The bug system suggested four of them to me now as possible duplicates of this.) While there is a warning in the documentation, "Warning Reference of a $value and the last array element remain even after the foreach loop. It is recommended to destroy it by unset()." an example would be helpful to illustrate what the effects of that can look like to a developer. Plus it would make the warning box larger and more visible. An example such as: Test script: --------------- <?php $array = [1, 2, 3, 4, 5]; foreach ($array as &$n) { // $n is a reference to an item in $array $n = $n * 2; } // $array == [2, 4, 6, 8, 10] // without an unset($n), $n is still a reference to the last item: $array[4] foreach ($array as $k => $n) { // $array[4] will be updated with each value from $array... echo "{$k} => {$n} "; print_r($array); } // ...until ultimately the second-to-last value is copied onto the last value // output: // 0 => 2 Array ( [0] => 2, [1] => 4, [2] => 6, [3] => 8, [4] => 2 ) // 1 => 4 Array ( [0] => 2, [1] => 4, [2] => 6, [3] => 8, [4] => 4 ) // 2 => 6 Array ( [0] => 2, [1] => 4, [2] => 6, [3] => 8, [4] => 6 ) // 3 => 8 Array ( [0] => 2, [1] => 4, [2] => 6, [3] => 8, [4] => 8 ) // 4 => 8 Array ( [0] => 2, [1] => 4, [2] => 6, [3] => 8, [4] => 8 ) ?> ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=71458&edit=1