Developer credits
Git commits in Moodle 3.4.0 by Danny Jung
commit 36a7651de251471d08f80fc9c6cc1146dbaa7995 Author: Danny Jung <dannyjung90@gmail.com> Date: Sat, 27 May 2017 03:02:58 +0800 Tag: v3.4.0-beta MDL-59073 Workshop: Prevent submission without content or file