MySQL 8.0 / libmysqlclient21 incompatible it's own libmysqlclien20 and with MariaDB /usr/share/mysql/charsets

If was discovered that the contents of /usr/share/mysql/charsets in MySQL 8.0 is incompatible with previous versions of MySQL and MariaDB. This causes issues on e.g. Ubuntu, where users have both MySQL 8.0 and MariaDB 10.3 available in the repositories (in Ubuntu 20.04). Both of the servers cannot be co-installed at the same time, but some parts of the clients can, and certainly software compiled against on client library can run with the other.

If was reported that if MythTV is compiled with libmysqlclient21, it will crash when running when /usr/share/mysql/charsets from MariaDB 10.3 is installed.

To mitigate this diversion in /usr/share/mysql/charsets compatibility, next version of MariaDB (10.5 or 10.6) could start using charsets in its own path, e.g. /usr/share/mariadb/charsets

See also:

• https://bugs.launchpad.net/ubuntu/+source/mysql-8.0/+bug/1877504 (specifically states "after upgrade libmysqlclient21 from 8.0.19-0ubuntu5 to 8.0.20-0ubuntu0.20.04.1")
• duplicate: https://bugs.launchpad.net/ubuntu/+source/qtbase-opensource-src/+bug/1877183
• https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=961672