F18 DNF and history

[James Antill]

On Wed, 2012-06-20 at 08:28 +1000, Angus Salkeld wrote:
> On 19/06/12 10:51 -0700, Adam Williamson wrote:
> >On Tue, 2012-06-19 at 15:33 +0200, Ales Kozumplik wrote:
> >> On 06/19/2012 02:44 PM, Michał Piotrowski wrote:
> >> > Hi,
> >> >
> >> > I have a question about DNF https://fedoraproject.org/wiki/Features/DNF
> >> >
> >> > Are there any plans to replace yum with dnf in the future?
> >> >
> >> > According to what is written here
> >> > https://github.com/akozumpl/dnf/wiki/Features-Considered-for-Dropping
> >> > history function will likely be dropped.
> >> >
> >> >  From my POV history feature is very useful. Is there a plan to provide
> >> > history function in Fedora dnf if yum gets dropped?
> >> >
> >>
> >> Hi Michal,
> >>
> >> Thanks for pointing this out. I considered history a candidate for
> >> dropping because I didn't realize people had usecases for it. It is not
> >> present in the early versions of DNF but I will make sure to put it back
> >> in later.
> >
> >Just to add my voice to the choir, I use it extensively and I suspect
> >many others in QA group too. It's extremely useful when trying to
> >determine exactly what update caused a given problem.
> 
> Maybe a "yum history bisect" would be a neat feature?

 I thought about implementing this, when I did "yum history rollback"
the problem is that you can only go "forwards". So say you have:

# yum history list
4 up
3 up blah
2 up bar
1 up foo

...then a bisect looks like:

# yum history list
5 rollback to 2
4 up
3 up blah
2 up bar
1 up foo

# yum history list
6 2=>1 or 2=>3
5 rollback to 2
4 up
3 up blah
2 up bar
1 up foo

...etc. and it seemed like it'd be too horrible to live with that in the
history. In theory we could add a feature so that "when you are finished
with the bisect" you can remove or merge the history for all the
transactions where the end rpmdb versions are the same. But it's not
obvious that adding features to remove things from history is a good
idea, in general.