v4: a handle with this instance's own host names the local user — another instance writes bob from here as bob@gerbeur.example, so a mention or a link copied from there named no one here: /@bob@gerbeur.example was a 404, and the mention notified nobody. localHandle (shared/validation.ts) drops this instance's host, its API's or its pages', from a handle; resolveUsername reads names by it, so the page, the API and the Open Graph 301 reach bob at /@bob, and so do the mention notifications and the chat's highlight and chime.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/test/middleware/og.test.ts

@@ -145,6 +145,7 @@ test("ogMiddleware: a former slug, a former name or another case gets a 301", as
       [`/@OLD_NAME/dumps/now`, dump.path],
       [`/@old_name/follow/playlists`, `/@${user.username}/follow/playlists`],
       [`/@${user.username.toUpperCase()}`, `/@${user.username}`],
+      [`/@${user.username}@gerbeur.test/upvoted`, `/@${user.username}/upvoted`],
     ]
   ) {
     const { res } = await handle(ogApp(), from);