history undo weirdness

[Honza Šilhan]

> From: "Michael Schwendt" <mschwendt at gmail.com>
>
> On Wed, 21 Oct 2015 23:44:53 +0200, Antonio M wrote:
> 
> > when I try to revert to a previous history I get an error...what does it
> > mean??
> > 
> > # dnf history undo 125
> 
> > @updates
> > Nessun pacchetto sssd-ipa-0:1.13.0-4.fc22.x86_64 disponibile.
> > Errore: An operation cannot be undone
> 
> You can only downgrade to packages, which are still available in
> the repos. Unfortunately, when an update is released, it replaces
> the previous update in the repo.

True. If you have "unlimited" disk on your machine, you can set `keepcache=1`
in `/etc/dnf/dnf.conf` file. That would preserve all packages that were downloaded
in the cache so they would always be available for history commands.
In yum this option was set by default, in DNF after many complains
it was turned off [1].

Honza

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1046244