Re: Scriptable interface for "set package selection to this set"

Hi!

On Thu, 2024-02-29 at 15:34:48 +0900, Simon Richter wrote:
> As far as I can see, there are two things apt and dpkg disagree on:
> 
>  - whether apt itself is Essential
> 
> This is understandable, apt special-cases itself, and for a good reason. I
> have no problem hardcoding an "apt install" into my package selection, that
> solves this nicely.

Right. To me this seems to indicate apt should provide its own
interface to set selections (perhaps through apt-mark or similar), so
that then it can inject itself into dpkg worldview as it does when
operating itself.

>  - whether e2fsprogs is Essential
> 
> This is only Important, not Essential, so dpkg marks it "deinstall", and apt
> doesn't want to remove it.

As Niels has pointed out, this would work automatically (for dpkg), if
e2fsprogs used Protected instead of Important.

> The obvious problem with this interface is that half of it is provided by
> one tool, and half of it by another, and these implementations have
> incompatible worldviews that the user of the interface needs to be aware of,
> because it was never designed to be cohesive. Also, the name
> "dselect-upgrade" suggests that this is really an atavism. A useful one, but
> nonetheless probably not meant to be officially supported.
> 
> Since this functionality is useful, it would be nice to have a proper
> supported way to do this.

I think the different worldviews are ok, but as mentioned above, and
to avoid layer violations, to me this seems like the upper layer would
need to provide a wrapper for it.

If there's stuff to improve from the interface in the dpkg side I'm
happy to also discuss that.

Thanks,
Guillem