Made a first round of review, looking great!
I'll try to apply this to one of my machines running MySQL server to see how transition works.

@joneum and @brnrd -- what are your opinions? :)

In D43946#1008473, @tcberner wrote:

@joneum and @brnrd -- what are your opinions? :)

okay for me, even if I have to rewrite MySQL 82 and 83 :-)

To ease reviewing separate commits, here's a GitHub PR: https://github.com/arrowd/freebsd-ports/pull/9

Next to mysql:server and mysql:client there should be a mysql:lib. Many ports depending on client actually need the library only.

Complicating here is that then you have even more conflicts between those. You even have to maintain multiple mariadb-connector-c versions for various MariaDB versions. Likely in MySQL too.
This involves a level of cmake skill, knowledge and experience I simply do not have.

The number of @comment lines in MariaDB plist is because the MariaDB CMake stuff does not allow for the way FreeBSD ports work. Building SERVER without CLIENT is not a thing. The SERVER and CLIENT options are broken; not all files are properly put in either.

Looong ago I have taken maintainership so the ports would actually be updated timely. If anyone with more CMake skillz wants to take over, I'd happily hand over or participate in a mariadb or mysql team.
New versions take considerable effort to port, some of the engines are broken (COKLUMNSTORE, ...).

Next to mysql:server and mysql:client there should be a mysql:lib.

This change is about removing both mysql:server and mysql;client.

Many ports depending on client actually need the library only.

You're talking about splitting mysql-client into executables and library itself? I don't think we should do that in this change, rather wait for subpackages to arrive and then reconsider.

You even have to maintain multiple mariadb-connector-c versions for various MariaDB versions.

Why? Right now the port doesn't seem to depend on anything server-ish.

One thing that I'm unsure about is the need to migrate /usr/local/etc/mysql/my.cnf to /usr/local/${SERVER}/etc/mysql/my.cnf. While I mention this in UPDATING it still feels like there is a high chance that end users would just do pkg upgrade without reading anything.

But this may be not that bad at all, because problem would arise only if a user made changes /usr/local/etc/mysql/my.cnf.

Another approach would be making mysql clients use /usr/local/etc/mysql/client.cnf as a default config file and then make the /usr/local/etc/mysql/my.cnf location deprecated, like we already did for /usr/local/etc/my.cnf.