Re: Pinning vs. conflicting

[Matthias Urlichs <matthias@urlichs.de>]

Hi,

Thorsten Glaser:
> >> You have not yet explained why apt pinning is not enough.
> 
> Simply because apt is not the only way to install packages.
> 
Don't synaptic and/or whatever honor these pins too?

> Right. Furthermore, pinning can be used by the local admin,
> without namespacing pin priorities or somesuch, so it’s not
> something packages should do.
> 
Since you don't need a package for creating a pin entry anyway, this is a
non-argument.

Why would you want to need a namespace for pin priorities?
-1 is sufficient to block installation and therefore doesn't conflict
with any other rules. What else would you need?

> There is another benefit: conflicting packages allow all
> package managers’ resolvers to find nice dependency chains,

… esp. since their dependency resolution algorithm ends up removing the
blocker package. As soon as there's the slightest hint of a conflict
*anywhere* in the dependency chain. Aptitude is notorious for this.

… unless you add a pin. In which case you can add a pin to prevent
systemd{,sysv} from installing anyway.

-- 
-- Matthias Urlichs