User blog comment:Adnoam/Item lists/@comment-30321884-20190404205358/@comment-30321884-20190405144150

The real problem may appear if some entry will break Lua syntax. I guess, the whole module will thus throw an exception rather then return an array of elements. In this case we will see, - I don't know, - an empty space wherever the module is invoked?

To be fair, I'm not familiar neither with Lua nor with mediawiki templates. (Yet.) But I may suggest one thing. :)

Let's assume there is maintenance parameter Test. When it's set to "yes", the main module runs another routine, which sole purpose is to check the consistency of data modules. Whether they load properly, whether each entry contain all the required settings, and whether they set as expected. The output then would be simply a report of errors encoutered. Or a single line of approvement like "Module:ItemsDB/Hats is fine!" And there might be some test page, where contributors may check if everything is okey after their edits.