Suggest symlinking compatible components to their libmysqlclient equivalents

The following exist in popular software (like Ruby's mysql2 connector)

mysql_version.h -> mariadb_version.h
mysql_com.h -> mariadb_com.h

Failing client ebuilds in gentoo (incomplete list as of now):

• dev-python/mysqlclient
• sci-libs/gdal
• dev-ruby/mysql2
• net-analyzer/net-snmp
• dev-db/mysql++

Btw, mysqlclient-1.3.12 seems to be fixed

sysbench also includes mysql_version.h. And the only reason for that was compatibility with MariaDB 10.2. Starting from MariaDB 10.2 it is insufficient to include mysql.h to have MYSQL_VERSION_ID defined, that's why sysbench also includes mysql_version.h, which breaks MariaDB compatibility again in 10.2.8.

As I understand, 10.2.9 will include a compatibility header throwing a compile-time warning. Which leaves me wondering what's the correct AND portable way to have MYSQL_VERSION_ID defined?

It's a warning saying "Don't include this file directly, include <mysql.h>"
mysql.h is (as we've understood) the only documented C API header, and it's always sufficient, client programs don't need to include mysql_version.h, mysql_com.h, or anything else from /usr/include/mysql. This is the case with MariaDB Connector-C too.

OK, after looking more into it, here's the code in sysbench that required including mysql_version.h:

#if !defined(MARIADB_BASE_VERSION) && MYSQL_VERSION_ID >= 80001 && \

  MYSQL_VERSION_ID != 80002 /* see https://bugs.mysql.com/?id=87337 */

typedef bool my_bool;

#endif

I.e. due to MySQL-specific issues, I must be able to tell between MariaDB and MySQL. So I thought using MARIADB_BASE_VERSION for that purpose was a good idea. And it was until MariaDB 10.2, which requires including mysql_version.h, including mysql.h is not enough. Is there a better way to do it?

I see. First, your mysql_version.h include is redundant. In

#include <mysql.h> 

#include <mysql_version.h> 

you can safely drop the second line, because mysql.h includes mysql_version.h anyway. That's what I meant by "it's always sufficient". In libmysqlclient, it includes mysql_version.h, in libmariadb mysql_version.h is renamed and mysql.h includes the renamed file.

Now, the problem is that libmariadb headers don't define MARIADB_BASE_VERSION. I will fix that. And you'll be able to include only mysql.h — which will work in any MariaDB or MySQL version, and test for MARIADB_BASE_VERSION as before.

I've tested that with these changes sysbench (latest from github) builds fine.

Thanks! So I have the following choices:

1. Leave everything as is. This will work for MariaDB < 10.2.8, not work for MariaDB = 10.2.8, will work with a warning for MariaDB > 10.2.8

2. Remove the redundant #include <mysql_version.h> line. This will work for MariaDB 10.2.8, will break 10.2.x, where x < 8

3. Do some configure-time pushups to test for server/mysql_version.h availability, and if available, include that one instead of just mysql_version.h. Which will apparently work everywhere.

It looks like #3, as ugly as it is, provides better compatibility.

Oh, right. Then the easiest fix would be this:

--- drv_mysql.c.old     2017-09-15 10:14:09.000000000 +0200

+++ drv_mysql.c 2017-09-15 10:13:40.000000000 +0200

@@ -35,7 +35,6 @@

 #include <stdio.h>

 #include <mysql.h>

-#include <mysql_version.h>

 #include <mysqld_error.h>

 #include <errmsg.h>

@@ -50,8 +49,8 @@

 #define SAFESTR(s) ((s != NULL) ? (s) : "(null)")

-#if !defined(MARIADB_BASE_VERSION) && MYSQL_VERSION_ID >= 80001 && \

-  MYSQL_VERSION_ID != 80002 /* see https://bugs.mysql.com/?id=87337 */

+#if !defined(MARIADB_BASE_VERSION) && !defined(MARIADB_VERSION_ID) && \

+  MYSQL_VERSION_ID >= 80001 && MYSQL_VERSION_ID != 80002 /* see https://bugs.mysql.com/?id=87337 */

 typedef bool my_bool;

 #endif

As far as I understand it should work for all MariaDB and MySQL versions.

kaamos, could you, please, confirm that the patch above worked for you? If not — I'll try to come up with something that does.

@serg, sorry, I missed the last 2 comments (no emails, not even in the spam folder), so I implemented #3 from my list.

I tested your patch just now and it works with MySQL, MariaDB 10.1 and MariaDB 10.2.8. I'm going to replace my (ugly) fix with yours. Thanks a lot!

Thanks! Pushed.