On Tue, Feb 16, 2021 at 09:17:13AM -0500, Stefan Monnier wrote:
> > Therefore, you'll find apretty advanced alternatives system
> > for client-y stuff in Debian (editor, MUA, what not) but
> > not for server-y stuff.
>
> Hmm... so that's your take on it?
> Maybe you're right. I was thinking of the display manager as
> a counter-example (you can install lxdm, gdm, and others simultaneously
> even though you can only use one at a the same time), but you might
> argue that it's not "server-y stuff".
Exactly. This is user-y stuff: imagine two X servers running on behalf
of two users (some time ago, those were a separate hardware: remember
those shiny HP thingies with a whopping 6 MB of RAM and a huge monitor?
This was before HP specialised on building inkjets of [CENSORED]
quality.
> Still, there is to me no good reason not to allow installing both exim
> and postfix at the same time. I think it's just a tradeoff between how
> often this could be useful and how much work it takes to tweak the
> packages.
Absolutely. I think the "alternatives" system isn't the right approach
to this. Rather make things co-installable and co-runnable (as PostgreSQL
does with its different versions)
The start (@Kevin: still listening?) would be to unpackage a package,
hack the Conflicts: (& friends) fields, try to install both and watch
the fireworks. Then fix the issues one by one.
I don't expect a huge amount of them (server ports, common directories,
those could be even found out by package inspection).
> Also, as someone who happens to prefer Postfix to Exim (no particular
> reason: I'm just familiar with Postfix and not with Exim), I'm actually
> happy that `apt install postfix` gets me rid of Exim instead of having
> it linger uselessly.
Yep. In the normal case, this is what the overstressed admin wants :)
> But I do think Debian's packaging system should be improved to
> accommodate such needs: it should be possible and easy to override
> conflicts so as to force-install both Postfix and Exim (for instance).
> [ and I don't mean it just when you install the second package, but
> also during the rest of the lifetime of the system, until you remove
> the override. ]
ISTR there was an apt option ("force") to override such things.
Of course you end with a package database in a "strange" state;
perhaps the database isn't prepared to contain a package set
which has dependency conflicts. I don't even know what a dependency
resolver will do in such cases. But there was at least one
--force-depends option (which isn't mentioned in the man page
these days).
Cheers
- t
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