Problem: Currently some statements with links to pages on other projects, like for example Commons category (P373), are stored as a string datatype. That creates several types of issues:
prevents automatic detection if the pages actually exist
non-uniform storage format (spaces vs. underscores in page name) makes it hard to detect duplicates
lack of integration with page moves and deletions
Many of the above issues are being managed through property constraints, but the maintenance would be much simpler if the underlying datatype was more similar to CommonsMedia datatype or to the sitelinks.
Who would benefit: maintainers who work on keeping those links up to date. Currently there is a big backlog of constraint violations for many properties holding links to Commons pages.
Proposed solution: There are several possible solutions:
Create a new datatype for links to Commons pages or to pages on other projects
You know, this would be fixed if Wikidata didn't need an unhealthy dose of including categories on pages about topics, and instead managed these through item statements to category items. But, you know, the world might melt from climate change before that happens. --Izno (talk) 03:24, 16 November 2017 (UTC)
Izno This is not about about article-items and category-items, but about how we save links to pages on other projects. String datatype just does not work well for that purpose. --Jarekt (talk) 13:37, 16 November 2017 (UTC)
You're making my point for me. We should save links for article items on article items and category items on category items, and then link the items, even if that means creating new items, not the really dumb mix that is employed today. --Izno (talk) 14:20, 16 November 2017 (UTC)
Move/deletion integration seems problematic. How would you act on a page being deleted and undeleted? Or deleted and rewritten? Or a noticeboard page being moved because someone prefers that method of archival? --Tgr (WMF) (talk) 04:02, 20 November 2017 (UTC)