Bug #12001 C API - mysql_next_result()

Description:
When running multiple queries and the last one fails, the mysql_next_result() returns -1 (which means successfull completion and last result) instead of >0 for error. Queries ran after that, fail.

No problem when the bad query is in the middle.

How to repeat:
const char *multiSQL=
                   "DROP TABLE IF EXISTS test_table;"
                   "CREATE TABLE test_table(id INT);"
                   "INSERT INTO test_table VALUES(10);"
                   "UPDATE test_table SET id=20 WHERE id=10;"
                   "SELECT * FROM test_table;"
                   "INSER INTO non_existent_table VALUES(11);"
		   ;
if(0==mysql_real_query(&conn,multiSQL,(unsigned long)strlen(multiSQL)))
{
	MYSQL_RES *result=NULL;
	if(mysql_field_count(&conn)>0)
	{//Clear result in case there is a result.
		result=mysql_use_result(&conn);
		if(NULL!=result)
			mysql_free_result(result);
	}
	while(1)
	{
		res=mysql_next_result(&conn);
		if(mysql_field_count(&conn)>0)
		{//Clear result in case there's a result.
			result=mysql_use_result(&conn);
			if(NULL!=result)
				mysql_free_result(result);
		}
		if(res>0)
		{
			printf("FAIL\n");
			break;
		}
		else
		{
			printf("OK\n");
			if(res==-1)//last one. Gets in here on ERROR too, why?
			{
				printf("\nLast one :-).");
				break;
			}
		}
	printf("\n");
}//while(1)
else
{
	printf("FAIL\n");
}

Work around: Just add "SELECT 1" or some other meaningless query to the bunch.

Works fine without SELECT queries.

Tested on Win 2003 , Microsoft Visual C 7.0. Test case is attached.

Test case

Attachment: test.c (text/plain), 1.77 KiB.

And Vasily? What happened? :-D

Only affects 4.1 - works ok with libmysql 5.0

Happens to me with 5.0 library too (sending query to 4.1 server).

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/internals/27305

patch pushed into 4.1.14

Documented in 4.1.14 changelog.