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From: zimoun <zimon.toutoune@gmail.com>
Subject: =?UTF-8?Q?Re=3A_Speeding_up_=E2=80=9Cguix_pull=E2=80=9D=3A_splitting_modules?=
Date: Fri, 10 Jan 2020 13:53:38 +0100
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To: =?UTF-8?Q?G=C3=A1bor_Boskovits?= <boskovits@gmail.com>
Cc: Guix Devel <guix-devel@gnu.org>

Hi G=C3=A1bor,

On Fri, 10 Jan 2020 at 13:42, G=C3=A1bor Boskovits <boskovits@gmail.com> wr=
ote:

> > 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