The data source class does not exist
If you get the following during an upgrade, particularly from early Moodle 3.x versions to later, it means you need to first remove the
localcache folders in your data directory.
!!! Coding error detected, it must be fixed by a programmer: The data source class does not exist. !!! !! Error code: codingerror !! !! Stack trace: * line 506 of /cache/classes/definition.php: coding_exception thrown * line 534 of /cache/classes/helper.php: call to cache_definition::load() * line 493 of /cache/classes/helper.php: call to cache_helper::purge_store() * line 175 of /admin/cli/upgrade.php: call to cache_helper::purge_all()