Re: Speeding up “guix pull”: splitting modules

[zimoun]

Hi Gábor,

On Fri, 10 Jan 2020 at 13:42, Gábor Boskovits <address@hidden> wrote:

> > The modules graph (DAG) is already available. :-)
>
> The main problem here is that the modules do not form a DAG.
> There are circular dependencies between the modules.
> If those were not, then modular build would be possible, but because of
> the spaghetti we are forced to build these together.

Maybe we have a naming problem. :-)

I agree that it is not an Acyclic graph and if I understand you
correctly it is because there are cycles that the mess starts.

Using the Directed properties (but not required in fact, whatever :-),
traversing the graph detects the cycle. It is more or less what it is
done in the function `guix/import/utils.scm (topological-sort)`.

So knowing where the cycles are could help to transform the DaG (not
fully acyclic yet) to a DAG. :-)


All the best,
simon