I found during preupgrade process from F16 to F17 that preupgrade does not
verify that the packages downloaded for the upgrade are not corrupted.
If any package is corrupted for any reason in preupgrade repo, this causes
the upgrade process to fail somewhere in the middle, leaving system in
unknown, often broken state.
Here is a bug I filled:
with a kind of patch I made.
It would probably be better for anaconda to verify packages
before installation, though. Or is there any other method of package
verifycation during preupgrade? For livecd, install dvd there is a
media check (while it is not asked for by default now, which is IMHO not
correct), but none for preupgrade I know about.