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From: "Dave Korn" <dk AT artimi DOT com>
To: <cygwin AT cygwin DOT com>
Subject: RE: Is setup.exe _supposed_ to delete the cygwin dll before attempting to run shell scripts?
Date: Mon, 27 Sep 2004 18:29:43 +0100
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X-OriginalArrivalTime: 27 Sep 2004 17:29:44.0501 (UTC) FILETIME=[942AA650:01C4A4B7]

> -----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.

    cheers, 
      DaveK
-- 
Can't think of a witty .sigline today....


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