[Aptitude-devel] Bug#1079710: Bug#1079710: aptitude: "Immediate dependency resolution" must be optional

[Matthias Urlichs]

On 26.08.24 19:12, Julian Andres Klode wrote:
> Note that upgrading systems with aptitude is not supported

IMHO updating systems ultimately is the job of dpkg, and unless I'm 
throwing around various force-whatever options it doesn't matter *at 
all* which tool I use to call "dpkg -i", as long as I do it at least 
once per package and in roughly the correct order.

In any case this is just one example of how to get aptitude into a state 
that it can't easily get out of and which exhibits this problem. There 
are others. I've hit this multiple times during my 20 years of using 
Debian with smaller conflict sets, but the time-64 transition is 
annoying enough so I'm finally asking the maintainers to please fix it, 
or at least add a workaround people can live with, as my C++ foo isn't 
up to the task.

I'm not asking for another tool that can do the job better or differently.

> But I don't quite understand what your goal is here.

My goal is to quickly resolve problems manually that aptitude's built-in 
resolver cannot handle because it consistently tries to uninstall gnome 
or wine-i386 when they happen to conflict with my self-built package, 
five library dependency levels down.

That, or it fails to arrive at a solution in less than an hour and/or 
asks me whether I want it to continue. Umpteen times.

The time-64 transition is *difficult*. It replaces 150+ libraries and 
any conflict whatsoever can throw aptitude's resolvers into a tailspin.

>   If you don't
> resolve again after making a change you don't know what is broken
> then, you can only guess.

It's trivial to discover exactly what's broken with aptitude. You press 
"g" and then select "Close".

You can then use the list of packages with unresolved problems (it's 
right at the top) to fix conflicts manually, the way you want to, until 
the "real" resolver is again able to find a possible solution using less 
than 100GB memory and/or less than five weeks' runtime.

If you never ended up in that kind of situation, consider yourself lucky.

> In any case, isn't this option already there?

Unfortunately, no it's not. This setting doesn't change aptitude's 
behavior in this case.

=====

What I want is simple. I want to press "+" or "-" on a specific package 
version, and I want this action to change the intended state of that 
package *and nothing else*. If that results in ten other packages to be 
uninstallable, that's on me.

Debian currently does not have an interactive tool that can do this. 
IMHO it's important to fix this.

There'll always be intractable situations. Package dependency resolution 
is NP-complete after all.

No, using the command line to add hints will not fix this. You want to 
add every single time64 library until apt stumbles on the solution you 
want? be my guest.

-- 
-- Matthias Urlichs
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