This ticket can increase priority after we recognized that we need more reduce in DB. Here are latests brainstorm:

Possibly suspicious Lua code

• For loops
• Access the objects before specifying the language
• Looking for specifically modules https://en.wikipedia.org/wiki/Category:Wikipedia_modules

Investigation summary:

Category only changes that read from wikidata
We noticed https://tr.wikipedia.org/wiki/%C5%9Eablon:Kitap_bilgi_kutusu was tagged as using p18 image even though the wikipedia page doesn't include an image. This lead us to find the category No_local_image_but_image_on_Wikidata which checks Wikidata in order to assign a category, rather than to actually use the image.
This example also has no image, but uses p18 - https://en.wikipedia.org/w/index.php?title=Benson_Jack_Anthony&action=info

This lead to the hard/soft usage idea https://phabricator.wikimedia.org/T416822 , which could apply to category-only changes. However, use of a specific method for ‘soft (suppressed)’ usages would have to be done by the lua coders manually and is error prone (read more details on the ticket comments)

Actual no-op reads of wikidata
We also found modules which look up a wikidata item but then this does not affect the page or category. We worked on improving these modules and saw a decrease in unnecessary usage of P18 - see our communication with the community on this and the ticket

Frequent ‘subclass’ usages in French wikipedia
In the French Wikidata module, subclass is used by these two:
Excludes superclasses: looks like not used in many modules
https://fr.wikipedia.org/w/index.php?search=insource%3A%22excludesuperclasses%22+prefix%3AModule%3A&title=Sp%C3%A9cial%3ARecherche&profile=advanced&fulltext=1&ns0=1
Target superclass use in modules:
https://fr.wikipedia.org/w/index.php?search=insource%3A%22targetsuperclass%22+prefix%3AModule%3A&title=Sp%C3%A9cial%3ARecherche&profile=advanced&fulltext=1&ns0=1 E.g. https://fr.wikipedia.org/wiki/Module:Infobox/Fonctions/Personne p.specialrole() - used by “Notable Status” which checks the subclasses

Inside the timeline method, we have local statements = wikidata.wikidata.getClaims(wdconf) that goes here https://fr.wikipedia.org/wiki/Module:Wikidata
Inside getClaims we use filterClaims. excludesuperclasses is used in that.

In conclusion, investigations of this so far indicate that there is not a problem.

• if the chain of superclasses was broken, something different would be rendered on the page, so in this case (https://fr.wikipedia.org/wiki/Module:Infobox/Fonctions/Personne) it’s a correct nested usage.

Working document with the examples we investigated
https://docs.google.com/document/d/1kmw4kRJPpOPAy4zYg6p5TjVOU4yJmMtqXqFFZbAPkio/edit?tab=t.uwsag4suqczx

Further research:
More investigation could be done here but for now we are focusing on different areas so we will mark this ticket as done.