Any change to feed that could affect a package is supposed to trigger this, and that does include deleting a package, adding a package, or a detected change in any repodata files from any associated connectors. What happens is any operation like that sets an index dirty flag for the feed, and if a request is made for it after that, it is rebuilt. There is also a 30 second delay before this can get triggered, so if you:
- upload/delete a package
- wait 30s
- get repodata/repomd.xml
It should show an updated timestamp and revision.
We are currently moving to more of a job-based system for these index rebuilds, which also will provide better visibility into their creation and allow for manually triggering them. We're starting this process with Debian feeds since those exhibit the most problems with the current system, but plan to extend it to rpm and apk as well.
Anyway, if you're not seeing it update even after the 30s delay then there must be some other issue at work, so we'll need to dig into that.