Memory leak while reconnecting to server

Hi,

memory-leak is detected when the server is off and the client keeps reconnecting to it. Here is test code with steps how you can repeat the bug:

//--------------------------TEST CODE--------------------------------------

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

#include <iostream>

#include "mysql.h"

using namespace std;

int main(int argc, char** argv)

{

    int nRC = 0;

    MYSQL*   pMySQL = NULL;

    my_bool  bReconnect = 1;

    MYSQL_RES *pRes;

    pMySQL = mysql_init(NULL);

    mysql_options(pMySQL, MYSQL_OPT_RECONNECT, &bReconnect);

    if( mysql_real_connect( pMySQL, "127.0.0.1", "root", "",

                            NULL, 3306, NULL, 0) != NULL    )

        while(true) {

            if( (nRC = mysql_query(pMySQL, "SELECT 'hello world'")) == 0) {

                pRes = mysql_store_result(pMySQL);

                mysql_free_result(pRes);

                cout << "Query ok...." << endl;

            }

            else

                cout << "Query error, code: " << nRC

                     << ", msg: " << mysql_error(pMySQL) << endl;

            usleep(4000);

        }

    else

        cout << "Unable to connect to mysqld" << endl;

    mysql_close(pMySQL);

    return 0;

}

//----------------------------------------------------------------------

Step 1. Build the test code
Step 2. Start MySQL/Mariadb server
Step 3. Execute the test binary (in terminal or valgrind), and it would keep printing "Query OK"..
Step 4. Shut down MySQL/Mariadb server. And the client would keep printing "Query error..."
Step 5. Watch the memory usage of the test binary, and it would keep raising.

After debugging for a while, I thought the bug locates in function "mysql_reconnect" in file "libmariadb.c" around line 1992.

The original logic is to let a tmp_client to rebuild a new connection which has to allocate some structures such as hash_table for keeping the mysql_options. But when it fails to reconnect, the destructor "mysql_close" should be called in order to free the allocated memory. And it seems someone has fogot this point.

So after line 1992: my_set_error(mysql,..... )
I added this line as a test patch:
mysql_close(&tmp_mysql);

And it seems to work well without memory leak any more.
But I'm not 100% sure of it and looking forward for your response.

Thanks and best wish
Tianhong