Bug #79264 [NEW]: Value assigned by reference in foreach is do not overwrite to removed variable

From: juanparati at gmail dot com Operating system: Linux PHP version: 7.3.14 Package: Scripting Engine problem Bug Type: Bug Bug description:Value assigned by reference in foreach is do not overwrite to removed variable Description: ------------ It's very well documented that behaviour of variables passed by reference into a foreach can have unexpected behaviours when the variables were previosly used. From PHP 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(). Otherwise you will experience the following behavior" However I found that in some cases even when the variable used as reference is previously removed using "unset" the issue persist. I can reproduce this issue from PHP 5.6 TO PHP 7.4 with the same result. It seems that if variables previously are removed (unset) and used again as reference into the foreach can have a wrong behaviour. This issue is probably due the way that PHP keep the internal references. Test script: --------------- See the following code https://3v4l.org/h6d0G The array subnodes "needle" and "haystack" were automatically appended for the first element of the array even if the variable used as reference was previously removed (unset). In the following example the result is the expected one when the variables were not previously used: https://3v4l.org/4kRmH Expected result: ---------------- array(2) { ["18427e904f7a227e8c3b80dd2858a70e"]=> array(2) { ["needle"]=> array(1) { [0]=> array(3) { ["starts_at"]=> int(11821) ["ends_at"]=> int(14377) ["length"]=> int(2556) } } ["haystack"]=> array(1) { [0]=> array(4) { ["starts_at"]=> int(12227) ["ends_at"]=> int(14783) ["length"]=> int(2556) ["original"]=> string(3) "foo" } } } ["dd0c26f35ebf55de25eabea3edbfba32"]=> array(2) { ["needle"]=> array(1) { [0]=> array(3) { ["starts_at"]=> int(17255) ["ends_at"]=> int(32431) ["length"]=> int(15176) } } ["haystack"]=> array(1) { [0]=> array(4) { ["starts_at"]=> int(17776) ["ends_at"]=> int(33032) ["length"]=> int(15256) ["original"]=> string(3) "foo" } } } } Actual result: -------------- array(2) { ["18427e904f7a227e8c3b80dd2858a70e"]=> array(2) { ["needle"]=> array(1) { [0]=> array(1) { [0]=> array(4) { ["starts_at"]=> int(17255) ["ends_at"]=> int(32431) ["length"]=> int(15176) ["original"]=> string(3) "foo" } } } ["haystack"]=> array(1) { [0]=> array(1) { [0]=> array(4) { ["starts_at"]=> int(17776) ["ends_at"]=> int(33032) ["length"]=> int(15256) ["original"]=> string(3) "foo" } } } } ["dd0c26f35ebf55de25eabea3edbfba32"]=> array(2) { ["needle"]=> array(1) { [0]=> array(3) { ["starts_at"]=> int(17255) ["ends_at"]=> int(32431) ["length"]=> int(15176) } } ["haystack"]=> array(1) { [0]=> array(3) { ["starts_at"]=> int(17776) ["ends_at"]=> int(33032) ["length"]=> int(15256) } } } } -- Edit bug report at https://bugs.php.net/bug.php?id=79264&edit=1 -- Fix committed: https://bugs.php.net/fix.php?id=79264&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=79264&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=79264&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=79264&r=needscript Try newer version: https://bugs.php.net/fix.php?id=79264&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=79264&r=support Expected behavior: https://bugs.php.net/fix.php?id=79264&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=79264&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=79264&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=79264&r=globals PHP version support discontinued: https://bugs.php.net/fix.php?id=79264&r=phptooold Daylight Savings: https://bugs.php.net/fix.php?id=79264&r=dst IIS Stability: https://bugs.php.net/fix.php?id=79264&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=79264&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=79264&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=79264&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=79264&r=mysqlcfg