Bug #71863 [Asn]: Segfault when EXPLAIN with "Unknown column" error

Edit report at https://bugs.php.net/bug.php?id=71863&edit=1 ID: 71863 Updated by: andrey@php.net Reported by: Azq2 at ya dot ru Summary: Segfault when EXPLAIN with "Unknown column" error Status: Assigned Type: Bug Package: MySQLi related Operating System: Ubuntu 14.04 PHP Version: master-Git-2016-03-20 (Git) Assigned To: andrey Block user comment: N Private report: N New Comment: Here is an example of MariaDB. A test from the suite fails. Why? Because they changed a text message, which is not that weird, but they changed the ID of the error. 001+ int(2) 002+ int(1146) 003+ string(39) "Table 'mysql.table_stats' doesn't exist" 001- int(1) 002- int(1051) 003- %unicode|string%(%d) "Unknown table %snot_exists%s" Previous Comments: ------------------------------------------------------------------------ [2016-07-22 20:42:35] andrey@php.net MariaDB bends the protocol and this is why this happened. I am preparing a fix for this. The crash happens because of a bug of mine of not initializing correctly callbacks for the error structure. Reporting an error after reporting that there is no error is very rare case, which I saw last time in 2007 (see http://bugs.mysql.com/bug.php?id=27876 :) mysqlnd should not crash, that is for sure. ------------------------------------------------------------------------ [2016-07-22 20:26:45] reyad dot attiyat at gmail dot com This segfault only happens in PHP 7.1 and not in previous versions of PHP. I understand that mysqlnd only supports the official MySQL implementation, but don't believe we should have a separate driver for MariaDB or other forks (like AWS Aurora). Do you think we should add a quirk/flag to the mysqlnd driver for MariaDB that would handle these errors correctly? ------------------------------------------------------------------------ [2016-07-22 20:03:56] andrey@php.net MySQL sends an error directly after the query is executed, as it should happen. MariaDB does send OK, meaning that there are fields and sends meta for 10 fields, then EOF (marking end of metadata) and only then it sends an error message. Such sending of errors is not common. It exists when we talk calling stored procedures because they can fail in the middle after some meta is sent. ------------------------------------------------------------------------ [2016-07-19 19:10:20] andrey@php.net I confirm a segfault with MariaDB 10.1.16 . Will have to check how it is incompatible with the MySQL client server protocol. ------------------------------------------------------------------------ [2016-07-19 14:05:08] andrey@php.net MariaDB might be an issue. I don't know. Keep in mind that mysqlnd supports officially only MySQL and not any forks. I will try to get MariaDB up and running to test with it. Best, Andrey ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=71863 -- Edit this bug report at https://bugs.php.net/bug.php?id=71863&edit=1