mysqlnd: error message is inappropriate in some cases

[SakiTakamachi]

Description

This is an issue I noticed while working on this fix.
#11912

This line sets the CR_MALFORMED_PACKET error.

php-src/ext/mysqlnd/mysqlnd_wireprotocol.c

Line 2471 in f907a00

SET_CLIENT_ERROR(error_info, CR_MALFORMED_PACKET, UNKNOWN_SQLSTATE, "Malformed packet");

However, the CR_SERVER_GONE_ERROR error may already be set at this point.

php-src/ext/mysqlnd/mysqlnd_wireprotocol.c

Line 297 in f907a00

SET_CLIENT_ERROR(error_info, CR_SERVER_GONE_ERROR, UNKNOWN_SQLSTATE, mysqlnd_server_gone);

Therefore, a CR_MALFORMED_PACKET error is output when an CR_SERVER_GONE_ERROR error should be output.

Fatal error: Uncaught mysqli_sql_exception: Malformed packet in /var/www/html/test/test.php:11

I get the following error message in the same situation when building with libmysqlclient :

Fatal error: Uncaught mysqli_sql_exception: Lost connection to MySQL server during query in /var/www/html/test/test.php:11

The code to reproduce:

<?php

$driver = new mysqli_driver();
$driver->report_mode = MYSQLI_REPORT_ERROR|MYSQLI_REPORT_STRICT;

$mysqli = new mysqli("mysql", "root", "", "test"); // my env 

fgets(STDIN);
// Restarted mysql, then press enter

var_dump($mysqli->select_db("test2"));

PHP Version

PHP 8.0+

Operating System

No response

[nielsdos]

Fixed in 199e48b