Oops. Thanks for pointing this out!

We could use an abuse filter, but only for cases when the language is mentioned in the edit summary. So this cannot be the definitive solution. In fact, there is plenty of deprecated language codes around that are regularly purged from and re-added to items. (The rabbit hole starts at T44396.) We really need a solution for this.

Just in case you wanted to estimate the time needed, there are currently almost half a million (~0.4%) items with a string in kr:

In T394456#10829446, @Lydia_Pintscher wrote:

Do we know how many tools, etc assume that there is only one value there? How much and what are we going to break?

SpecialRecentChangesLinked inherits from SpecialRecentChanges. The deprecated code is probably SpecialRecentChanges::addWatchlistJoins, but this is already tracked in T132568.

I can't see how it could get parsed.

It's tempting, but I wouldn't recommend it. AbuseFilter/revert interface is for mass undoing actions (unless we have T335649) and does not give admins much control beyond that (it's also bound to the abusefilter-revert right).

Seems so:

Changing project tags to just ParserFunctions since this is where #if, #ifeq, etc. are implemented.

(With "that" I referred to the need for dealing with PCREs, but it was a little off.)

After T356984, these notifications are no longer sent. Continued at T379149 and T358087.

In fact, no caption was inserted, and the diff is correct. Still, it is strange. How could such an edit get saved?

In T350480#10781974, @Tacsipacsi wrote:

In T350480#10781913, @matej_suchanek wrote:

This is somewhat doable in Lua by loading MediaWiki:BlockedExternalDomains.json using mw.loadJsonData and performing a lookup whenever a URL from Wikidata is to be shown. But it's a bit costly.

I think “somewhat doable” is an overstatement: the description mentions MediaWiki:Spam-blacklist, and that one is practically impossible (its content would need to be compiled from PCREs to Lua patterns and then matched against – it’s not only prohibitively slow, it’d also likely result in totally unreadable and thus unmaintainable code).

This is somewhat doable in Lua by loading MediaWiki:BlockedExternalDomains.json using mw.loadJsonData and performing a lookup whenever a URL from Wikidata is to be shown. But it's a bit costly.

Workaround: https://www.wikidata.org/w/index.php?title=MediaWiki:Deletereason-dropdown&diff=2241374887.

User can put "und" in their babel: https://www.wikidata.org/wiki/Category:User_und.

They are always categorizable programmatically. The respective content handler just needs to provide a "side channel" for categorization. This could be for example a reserved JSON key or even a new MCR slot.

Somewhat similar problem as T62160: Edits by Babel AutoCreate tagged as mobile edit or T228959: Abusefilter's block with a "Mobile edit" tag.