Bug #78765 [NEW]: enhancement to json_decode : treat a JSON string with duplicate keys as invalid

From: bas5winkel at gmail dot com Operating system: Debian PHP version: 7.2.24 Package: JSON related Bug Type: Bug Bug description:enhancement to json_decode : treat a JSON string with duplicate keys as invalid Description: ------------ Duplicate key names are not allowed in the JSON format. If a json string containing duplicate keys is decoded with json_decode, json_decode simple overwrites the existing key. Just like json_encode returns NULL for other invalid JSON strings, could such an input also be treated as invalid? Maybe as an optional check as this is just a rare condition? Test script: --------------- <?php echo var_export(json_decode('{"a":"b","a":"c"}'),1); ?> Expected result: ---------------- NULL or an exception Actual result: -------------- stdClass::__set_state(array( 'a' => 'c', )) -- Edit bug report at https://bugs.php.net/bug.php?id=78765&edit=1 -- Fix committed: https://bugs.php.net/fix.php?id=78765&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=78765&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=78765&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=78765&r=needscript Try newer version: https://bugs.php.net/fix.php?id=78765&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=78765&r=support Expected behavior: https://bugs.php.net/fix.php?id=78765&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=78765&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=78765&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=78765&r=globals PHP version support discontinued: https://bugs.php.net/fix.php?id=78765&r=phptooold Daylight Savings: https://bugs.php.net/fix.php?id=78765&r=dst IIS Stability: https://bugs.php.net/fix.php?id=78765&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=78765&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=78765&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=78765&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=78765&r=mysqlcfg