Hello! > /usr/share/mysql/charsets .. > The location of these files causes the libmysqlclient20 client library > to consider them charset files from mysql, and it tries to use them. > > I think this behavior is wrong, as the charset files do not belong to > mysql, however it is not immediately causing user-visible issues.
These files are drop-in replacements for MySQL files. The fact that they in Debian with MySQL version 5.7.26-1 (or any other version that has ever been in Debian) work as you said without any user-visible issues is proof that the drop-in-replacement works. > Things are worse with mysql-8.0, not yet in Debian but packaged in > Ubuntu. In mysql-8.0 the charset file format is not compatible with the > older versions, and this causes the client library to segfault when > trying to use the charset files from mariadb. I have not checked what packaging changes MySQL 8.0 introduces and in how many ways it is breaks backwards compatibility, but I guess that while working on https://salsa.debian.org/mariadb-team/mysql/-/tree/mysql-8.0/debian/master those issues need to be addressed when the details surface. If libmysqlclient21 in mysql-8.0 heavily breaks backwards compatibility (e.g. major changes in charsets?) then we need to make sure that the package control properly conflicts with libmysqlclient20 or the equivalent from MariaDB.