nixos/pretalx: run pretalx-manage migrate on plugin changes and upgrades (#450102)

            "mysql.service"

          ];

          wantedBy = [ "multi-user.target" ];

          preStart = ''

          preStart =

            let

              versionString = lib.concatStringsSep "\n" (

                [ "pretalx-${cfg.package.version}" ]

                ++ map (plugin: "${plugin.pname}-${plugin.version}") cfg.plugins

              );

            in

            ''

              versionFile="${cfg.settings.filesystem.data}/.version"

            version=$(cat "$versionFile" 2>/dev/null || echo 0)

              version="$(cat "$versionFile" 2>/dev/null || echo 0)"

            if [[ $version != ${cfg.package.version} ]]; then

              if [[ "$version" != "${versionString}" ]]; then

                ${lib.getExe' pythonEnv "pretalx-manage"} migrate

              echo "${cfg.package.version}" > "$versionFile"

                echo "${versionString}" > "$versionFile"

              fi

            '';

          serviceConfig = {