Bug #70275 [NEW]: On recursion error, json_encode can eat up all system memory

From: royanee at gmail dot com Operating system: PHP version: 5.6.12 Package: JSON related Bug Type: Bug Bug description:On recursion error, json_encode can eat up all system memory Description: ------------ When json_encode encounters recursion or other errors it will return false (as long as you are not using the largely undocumented constant JSON_PARTIAL_OUTPUT_ON_ERROR). Unfortunately, it waits until after it has processed all of the data to return the error. This was a problem for me when I was attempting to export an application state in JSON. As I was using the CLI, it ate up all of the system memory and at best it would have returned false if I could have waited an eternity for it to finish. I've included a test script with a nice handful of circular object references. Test script: --------------- $max_num_objects = 20; for ($num_objects = 5; $num_objects <= $max_num_objects; $num_objects++) { echo PHP_EOL . 'Number of Objects: ' . $num_objects . PHP_EOL; // Create the objects and link them to each other. $objects = new stdClass; for ($i = 0; $i < $num_objects; $i++) { $objects->$i = new stdClass; } for ($i = 0; $i < $num_objects; $i++) { for ($j = 0; $j < $num_objects; $j++) { if ($i != $j) { $objects->$i->$j = $objects->$j; } } } $starttime = microtime(true); serialize($objects); echo '$objects serialize: ' . number_format(microtime(true) - $starttime, 3) . ' seconds' . PHP_EOL; $starttime = microtime(true); if (json_encode($objects) === FALSE) { echo 'JSON Error #' . json_last_error() . ': ' . json_last_error_msg() . PHP_EOL; } echo '$objects json_encode: ' . number_format(microtime(true) - $starttime, 3) . ' seconds' . PHP_EOL; } Expected result: ---------------- Finishes in less than a second, ideally in a negligible amount of time. Example: ... Number of Objects: 10 $objects serialize: 0.000 seconds JSON Error #6: Recursion detected $objects json_encode: 0.000 seconds Actual result: -------------- ... Number of Objects: 10 $objects serialize: 0.000 seconds JSON Error #6: Recursion detected $objects json_encode: 7.227 seconds -- Edit bug report at https://bugs.php.net/bug.php?id=70275&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=70275&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=70275&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=70275&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=70275&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=70275&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=70275&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=70275&r=needscript Try newer version: https://bugs.php.net/fix.php?id=70275&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=70275&r=support Expected behavior: https://bugs.php.net/fix.php?id=70275&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=70275&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=70275&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=70275&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=70275&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=70275&r=dst IIS Stability: https://bugs.php.net/fix.php?id=70275&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=70275&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=70275&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=70275&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=70275&r=mysqlcfg