Bug #72107 [NEW]: Infinite Recursion in Array Structure

From: php at abiusx dot com Operating system: OS X PHP version: 7.0.5 Package: Arrays related Bug Type: Bug Bug description:Infinite Recursion in Array Structure Description: ------------ By creating an array structure in the following format: $a=[]; $a['ref']=&$a; $a['val']=$a; Any PHP-only attempt at discovering this recursion will fail. Also, structures like RecursiveIterators will loop infinitely, unserialize(serialize($a)) also drops out the val part. Generally PHP behaves very weird and unexpectedly. I have not traced this in the Zend engine to see what is causing it, but my hypothesis is that accessing $a['val'] is creating a new copy of it every time (and my PHP-side tests confirm this). Test script: --------------- $a=['ref'=>&$a]; $a['val']=$a; var_dump($a); //normal, as expected var_dump(unserialize(serialize($a))); //half-arsed foreach (new RecursiveIteratorIterator(new RecursiveArrayIterator($a)) as $k=>$v) echo $k,"=>",@$v,PHP_EOL; //infinite loop Expected result: ---------------- At least RecursiveIterators should be able to distinguish this behavior, if serialize can not handle it. Or PHP internals should be changed in a way that this does not happen. Or these examples be marked as dangerous because they can possibly break applications. Actual result: -------------- Infinite Loop -- Edit bug report at https://bugs.php.net/bug.php?id=72107&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=72107&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=72107&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=72107&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=72107&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=72107&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=72107&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=72107&r=needscript Try newer version: https://bugs.php.net/fix.php?id=72107&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=72107&r=support Expected behavior: https://bugs.php.net/fix.php?id=72107&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=72107&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=72107&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=72107&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=72107&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=72107&r=dst IIS Stability: https://bugs.php.net/fix.php?id=72107&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=72107&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=72107&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=72107&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=72107&r=mysqlcfg