The repo states are

INIT
READY
EXPIRED
DELETED
PROBLEM

The normal progression is INIT->READY->EXPIRED->DELETED. While koji has api calls to move repos into the PROBLEM state, nothing has ever used them.

Normal builds use repos in the READY state, though the repo could be marked expired during the build. EXPIRED means no longer current and kojira will delete them after a waiting period.

There are certain ways that builds can happen from an expired repo. When repo is generated from a a past event id, it is marked expired at the start (because it does not represent the current state of the tag). Some tools generate such repos and trigger builds from them. As such, there is code that assumes that EXPIRED repos are usable. So we should avoid placing known bad repos in that state.

In particular, kojira will mark "stale" repos expired. We should probably change this to the problem state instead, and make sure that problem repos are dealt with in a sane way.