"sympa" package cannot be installed w/o uninstalling MariaDB, installing MySQL instead

[Markus Ueberall]

PROBLEM: It's impossible to install "sympa" when using MariaDB instead of MySQL as can be seen below.

[2017-12-13T17:44:36] root@testserver:/tmp# lsb_release -rd
Description: Ubuntu 16.04.3 LTS
Release: 16.04

[2017-12-13T17:45:14] root@testserver:/tmp# apt-cache policy sympa
sympa:
  Installed: (none)
  Candidate: 6.1.24~dfsg-1
  Version table:
     6.1.24~dfsg-1 500
        500 http://de.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages

[2017-12-13T17:45:22] root@testserver:/tmp# apt install sympa
Reading package lists... Done
Building dependency tree
Reading state information... Done
[…]
The following packages will be REMOVED:
  mariadb-client mariadb-client-10.2 mariadb-server mariadb-server-10.2 mariadb-server-core-10.2
[…]
The following NEW packages will be installed:
[…] mysql-client-5.7 mysql-server mysql-server-5.7 mysql-server-core-5.7 sympa

EXPECTATION: Either set of database related packages is good enough for sympa (which also requires sqlite3, btw)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[philippe lhardy (artlog)]

problem still exists on jammy.

( french install ) :

Les paquets suivants seront ENLEVÉS :
  mariadb-client-10.6 mariadb-client-core-10.6 mariadb-server mariadb-server-10.6 mariadb-server-core-10.6

[philippe lhardy (artlog)]

After digging here my conclusion :

sympa installs default-mysql-server

default-mysql-server does not mean current mysql installation but it really means default mysql implementation for current distribution.

As of today January 21th 2023 this default is mysql on ubuntu, while it is mariadb on debian.
See https://bugs.launchpad.net/ubuntu/+source/mysql-defaults/+bug/1670788

sympa should not force using default system implementation if one is already installed.

[philippe lhardy (artlog)]

So to provide a workaround for this issue on existing package it is possible to require apt to ignore default-mysql-server dependency by adding it in argument with a final '-' :

apt install sympa default-mysql-server-

will do it.