Bug #29992 [Com]: foreach by reference corrupts the array

Edit report at https://bugs.php.net/bug.php?id=29992&edit=1 ID: 29992 Comment by: qdinar at gmail dot com Reported by: fletch at pobox dot com Summary: foreach by reference corrupts the array Status: Not a bug Type: Bug Package: Scripting Engine problem Operating System: linux PHP Version: 5.0.1 Block user comment: N Private report: N New Comment: issue with var_dump shown at "[2011-07-13 06:48 UTC] martijn at twotribes dot com" is an independent thing; array element looks like it is somehow changed even if it is just only referenced, or it is shown by var_dump, ie might be var_dump shows an array element which is referenced from outside; i have googled about that issue and have found a comment at http://php.net/manual/en/language.references.php , "Dave at SymmetricDesigns dot com 9 years ago", (most voted) which shows that it is not only what is shown by var_dump, but the array element changes its behaviour. that issue is conceptually independent from explanations, which do not show the "&" in var_dump output, given here for this issue, because original array element needs not to become a reference itself to reproduce this issue, it is rewritten because it is referenced by $item. Previous Comments: ------------------------------------------------------------------------ [2016-05-20 14:34:55] ourtusenka at yandex dot ru I have the same problem with php 5.6 on OpenServer. Before I never meet it; I don't use reference. But foreach do the same with my array. So: foreach ( $items as $item ) { //..echo single $item } Last element of $items is disappeared; ------------------------------------------------------------------------ [2015-01-01 20:18:52] chealer at gmail dot com The problematic behavior behing this issue is being tracked in #62132. ------------------------------------------------------------------------ [2014-12-06 23:33:13] dave dot mittner at gmail dot com Though this may not be a "bug" it's certainly dangerous and unexpected enough to deserve the level of importance. As has been said, people expect the behavior of block-level scoping. I don't come from Java or C++. I've programmed PHP for over a decade. I don't expect this kind of scope treatment because of other languages. I expect it because it's a clean and logical practice that's far safer than the contrary. Best practice for *any* language is to assume limited scope in blocks. I've known that since I was a teenager. In short, this should be changed. Even if it's a hack like unsetting it, that's safer than the current processing model. And I don't buy that "we can't change it because people use it" crap. I've had to rewrite entire systems due to changes in how PHP works. Stuff breaking is a risk any time you update PHP and why you should pay attention to change lists. ------------------------------------------------------------------------ [2014-06-20 22:09:56] steve at fancyguy dot com I have done this intentionally in some very lazy prototypes. foreach($data as $k => &v) { if (meets_complex_precondition($k)) { break; } } // do some stuff with $v potentially modifying it later unset($v); Comes in handy on occasion when working recursively by reference in deep arrays. Neat trick like 'array_map(null, $arr1, $arr2)'. ------------------------------------------------------------------------ [2014-02-11 03:34:59] xjis at msn dot com well, i guess to be more exact, i should've said php doesn't have block scope support whereas java/c++ does. now i see that even javascript has added block scoping starting 1.7 (need to use 'let' instead of 'var' to declare block-scoped variables) ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=29992 -- Edit this bug report at https://bugs.php.net/bug.php?id=29992&edit=1