Since we moved the code for updating the message cache and the search index out of DerivedPageDataUpdater, the code is no longer triggered on undeletion and import. Since we are not relying on the PageUpdatedEvent to trigger the listener methods in SearchEventIngress and LanguageEventIngress respectively, they are only run on page edits.

Note that page moves are unaffected, because they do use PageUpdater.

Relevant patch: https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1069667

Possible solutiuons:

• revert the patch
• trigger the relevant update code directly from ImportableOldRevisionImporter and UndeletePage
• trigger the PageUpdatedEvent from inside DerivedPageDataUpdater::doUpdates, instead of doing it in PageUpdater.