history undo weirdness

[Michael Schwendt]

On Thu, 22 Oct 2015 12:02:07 +1030, Tim wrote:

> > 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. 
> 
> Makes a nonsense of having any downgrade/undo options then...

True. A lot of trial-in-error in there. Especially multi-level undo.
Even undoing the last transaction may result in problems, because almost
no package downgrade has been tested (since package updates are supposed to
go forward-forward-forward, and package scriptlets may even migrate some
things from old to new, but not revert that during a downgrade).

> I was struck by this with a recent update to google-chrome, it will not
> run on my computer any more.  It would of been handy to simply roll back
> to the prior version, and wait for the next update, and see if that was
> any better.  Can't do it...  Grr.

There used to be a Yum plugin to create a local repo for the downloaded
packages. One can simulate it a bit based on keepcache=1 and copying the
package cache contents to a local repo that would not be touched by the
infamour "dnf/yum clean all".