[Distutils] name of the dependency problem

[Trishank Karthik Kuppusamy]

On 4/15/15 9:28 AM, Justin Cappos wrote:
> Yes, it's another way to solve the problem.  Both backtracking 
> dependency resolution and ZYpp will always find a solution.  The 
> tradeoff is really in how they function.  ZYpp is faster if there are 
> a lot of dependencies that conflict.  The backtracking dependency 
> resolution used in Stork is much easier for the user to understand why 
> it chose what it did.
>
> An aside: I'm not necessarily convinced that you need to solve this 
> problem automatically, instead of just raising an error when it 
> occurs.  It should be quite rare in practice and as such may not be 
> worth the complexity to have an automatic solution for the problem.
>

ZYpp seems to assume that dependency resolution is an NP-complete 
problem 
(http://www.watzmann.net/blog/2005/11/package-installation-is-np-complete.html).

I agree that we need not solve the problem just yet. It may be 
worthwhile to inspect packages on PyPI to see which package is 
unsatisfiable, but I am led to understand that this is difficult to do 
because most package metadata is in setup.py (runtime information).

Where did you run into this problem, Robin?