Well, looks like it was easier than I thought, I just copied the missing addon from:

https://github.com/pkgr/addon-mysql

into  /usr/share/openproject/installer/addons/  and re-launched openproject configure.

It's completed with no errors. Openproject itself looks fine, updated to 8.3.0.

I just hope I did not mess anything by doing these steps!

Thanks.

Hi Stefano,

The addon-mysql was indeed removed deliberately in 8.3.0, but the installer also respects previous installations so it should not (and did not in our test environments) run into this error. This only means that default new installations will be asked to install a PostgreSQL installation. All existing installations that chose or use MySQL will continue to work even without addon-mysql. We suggest all installations to use PostgreSQL because some features of OpenProject (such as full text search) will not work without it. For too long, the packaged installation was suggesting we preferred MySQL instead because an addon to install it was provided.

By reverting the file /etc/default/openproject , you caused the wizard to look for a MySQL addon that no longer exists and resulted in this error. 

In short: You can safely update the file /etc/default/openproject` to include PostgreSQL, not MySQL addon and continue as before.

 Best,

Oliver

Hi Oliver,
thanks for the detailed explanation, that's exactly what I did. When apt-get started the upgrade, I was prompted about /etc/default/openproject, as detailed here below (sorry for the italian locale, but I'm sure you can guess the sequence):

apt-get dist-upgrade
[...]
Configurazione di openproject (8.3.0-1551969192.89a2231f.jessie)...

File di configurazione "/etc/default/openproject"
==> Modificato (dall'utente o da uno script) dopo l'installazione.
==> Il distributore del pacchetto ha fornito una versione aggiornata.
  Come procedere? Le opzioni sono:
   Y o I   : installa la versione del responsabile del pacchetto
   N od O  : mantiene la versione attualmente installata
     D     : mostra le differenze tra le versioni
     Z     : avvia una shell per esaminare la situazione
L'azione predefinita consiste nel mantenere la versione attuale.
*** openproject (Y/I/N/O/D/Z) [predefinito=N] ? D <-- the first time I checked the differences

Here's the 'diff' output:
--- /etc/default/openproject    2018-11-05 01:22:06.278306156 +0100
+++ /etc/default/openproject.dpkg-new   2019-03-07 15:53:18.000000000 +0100
@@ -1,10 +1,10 @@
# Generated by pkgr
-export APP_HOME="/home/openproject"
+export APP_HOME="/opt/openproject"
export APP_NAME="openproject"
export APP_SAFE_NAME="openproject"
export APP_GROUP="openproject"
export APP_USER="openproject"
-export APP_WIZARDS="legacy-installer,mysql,apache2,repositories,smtp,memcached,openproject"
+export APP_WIZARDS="legacy-installer,postgres,apache2,repositories,smtp,memcached,openproject"
export APP_RUNNER_TYPE="systemd"
export APP_RUNNER_CLI="systemctl"
export PORT=${PORT:=6000}
(END)

No new parameters, and I was using MySQL, non Postgres, so I decided to keep my old conf file:
File di configurazione "/etc/default/openproject"
==> Modificato (dall'utente o da uno script) dopo l'installazione.
==> Il distributore del pacchetto ha fornito una versione aggiornata.
  Come procedere? Le opzioni sono:
   Y o I   : installa la versione del responsabile del pacchetto
   N od O  : mantiene la versione attualmente installata
     D     : mostra le differenze tra le versioni
     Z     : avvia una shell per esaminare la situazione
L'azione predefinita consiste nel mantenere la versione attuale.
*** openproject (Y/I/N/O/D/Z) [predefinito=N] ? N  <--- Here I decided to keep the old conf
==============
The openproject package provides an installer. Please run the following command to finish the installation:
sudo openproject configure
==============
Elaborazione dei trigger per libc-bin (2.19-18+deb8u10)...

Please note that the 'N' answer is the default one, so it's possible that other users will see the same error while upgrading, if they have MySQL instead of Postgres installed. I mean, I deliberatlely reverted the /etc/default/openproject, but that's also the default choice (N, to keep the old file), so it's possible other users will just press Enter when prompted, and they'll get the error when running 'openproject configure' as suggested at the end of apt-get upgrade.

Anyway, glad the little problem was solved quickly.

May I ask you another question? Is it possible to easily transfer the database from MySQL to Postgres on a running Openproject with a few user and projects? Is there a tool or should it be done manually? Would you suggest to go for it or just to keep the running thing on MySQL?

Thanks again for your help!

Kind Regards,
Stefano

Hi Stefano,

you're being asked this dialog by debian because you changed the $APP_HOME variable in there instead of setting it as openproject config:set APP_HOME="/home/openproject". I would suggest to revert the file to the upstream version and set the variable like this instead.

May I ask you another question? Is it possible to easily transfer the database from MySQL to Postgres on a running Openproject with a few user and projects? Is there a tool or should it be done manually? Would you suggest to go for it or just to keep the running thing on MySQL?

Yes, there's https://pgloader.io/ which we have been using on OpenProject databases in the past. In usual installations, it is nothing more than creating the database in postgres an running pgloader mysql://user:password@localhost/dbname postgres://pguser:pgpassword@localhost/newdbname  We will prepare a detailed guide on how to migrate in case we deprecate or reduce support for MySQL in the coming months. For now there is nothing you need to do.

Best,

Oliver