Mail Archives: cygwin/2004/09/27/13:40:27
On Mon, 27 Sep 2004, Dave Korn wrote:
> > -----Original Message-----
> > From: cygwin-owner On Behalf Of Brian Dessent
> > Sent: 24 September 2004 23:34
>
> > Igor Pechtchanski wrote:
> >
> > > > You first get the depth-first order: D, C, B, A.
> > >
> > > <PEDANTIC>
> > > Properly speaking, the depth-first order will be B, D, C, A...
> > > </PEDANTIC>
> >
> > D'oh'
> >
> > > Unfortunately, this won't work when you have circular dependencies
> > > (e.g., cygwin <-> fileutils).
> >
> > Oh, did I forget to say the graph must be a DAG before starting? :)
> > Anyway, there are heuristics that could be used to find the best
> > "feedback set" of edges for which removal would result in an acyclic
> > graph. e.g. the one described at
> > <http://www2.toki.or.id/book/AlgDesignManual/BOOK/BOOK4/NODE182.HTM>
> >
>
> Deleting edges from a graph won't actually make a package that depends
> on another operate successfully without that other package present!
> OTOH what I think might work would be to identify loops in the full
> dependency graph and treat them as single packages that must be
> installed or uninstalled together - effectively encapsulating the loop
> inside a single node and thereby reducing the graph to a DAG.
And what would be the order in which you would run the preremove scripts
from all of the packages in the loop? Or are you saying that they should
be considered packaging errors, and let setup do what it may?
Igor
--
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