history undo weirdness

[Michael Schwendt]

On Sat, 24 Oct 2015 20:05:52 +0800, Ed Greshko wrote:

> The only time "undo" seems relevant is if you're working with
> updates-testing repo.

It cannot be generalised like that. Installing from _any_ repo, such
as updates-testing, may lead to upgrading something that cannot be
downgraded again afterwards.

However, "undo" works well enough in many cases where you simply install
something that can be removed again afterwards.