The recently added external repo timestamp check compares:

• the timestamp of the external repo
• the event timestamp for the Koji repo that uses it

While testing this, both @mfilip and I had some trouble.

In my case, the problem was that my postgres server did not have timezone set to UTC.

It appears that if the postgres server is configured with any timezone other than UTC, then the event timestamp stored in Koji can be off by that timezone offset. UTC does not seem to be the default, and it doesn't look like our docs instruct admins to adjust this setting.

Because of this, on my system the event timestamp for the newly generated repo was still older than the timestamp reported by the external repo. This lead to a repeating cycle of regens (which would have eventually stopped after the tz offset period).

In @mfilip's case, the problem appeared to go the other way. A Koji repo that was slighly older than the external one had a newet timestamp and the regenerations did not occur (but presumably would have eventually).

Even apart from the tz issue, comparing timestamps from two different sources is potentially tricky. We don't control the construction of external repos.