Wikidata/Notes/Watchlist integration

Discussion of user notifications about changes on Wikidata (with Brandon Harris)

• Users need to be notified about changes to data items used on a page they watch.
• That is, a corresponding entry should be injected into recentchanges and show on the Watchlist (and RelatedChanges, the RSS feed, etc)
• a new notification framework is being implemented for mediawiki, perhaps we can used that: mw:Echo (Notifications)
  • Echo could be generalized to also cover server-to-server communication, so we could use it as the sole mechanism of pushing changes to the client wikis.
• we may also want to insert a (null)revision into the page history
  • we'd need two extra fields: rev_external_change_size and rev_external_change_data; these would provide sufficient info to generate a diff for the data change.
• Data diffs are loaded from the repo via the api and displayed on the local page's diff page using rendering code in WikibaseLib.
• If a span of several revisions is diffed, including both text and data edits, the text diff is shown in one section and the data diff is shown in another.
• diff/rev navigation works as usual.
• how about permalinks?
• how about viewing old revisions? can we show the corresponding old state of the data?
• once we have all this working, can we do the same for templates and images?