[RFC] Raise warnings for json_encode() and json_decode() issues

Hi internals. As my initial thread about introducing warnings to the JSON functions was not immediately flooded with disagreement I took the liberty of creating an RFC for official discussion. The proposal is to have json_encode() and json_decode() raise warnings whenever a failure occurs, instead of requiring the developer to call json_last_error() each time. The functionality of json_last_error() and json_last_error_msg() are unaffected and they can still be used in exactly the same way they are today https://wiki.php.net/rfc/json_encode_decode_errors Thanks, Craig