Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm
List-Subscribe: <mailto:cygwin-subscribe@cygwin.com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin@cygwin.com>
List-Help: <mailto:cygwin-help@cygwin.com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner@cygwin.com
Mail-Followup-To: cygwin@cygwin.com
Delivered-To: mailing list cygwin@cygwin.com
Message-ID: <4154A0D5.C117AA80@dessent.net>
Date: Fri, 24 Sep 2004 15:33:57 -0700
From: Brian Dessent <brian@dessent.net>
Organization: My own little world...
MIME-Version: 1.0
To: cygwin@cygwin.com
Subject: Re: Is setup.exe _supposed_ to delete the cygwin dll before attempting to run shell scripts?
References: <NUTMEG1Ed28kIN4MmXK000000d1@NUTMEG.CAM.ARTIMI.COM> <NUTMEGljWwY0VnkB4lt000000d7@NUTMEG.CAM.ARTIMI.COM> <20040924164839.GJ674@trixie.casa.cgf.cx> <20040924170321.GL12802@cygbert.vinschen.de> <Pine.GSO.4.61.0409241356130.880@slinky.cs.nyu.edu> <011d01c4a266$19792470$78d96f83@robinson.cam.ac.uk> <Pine.GSO.4.61.0409241526430.20381@slinky.cs.nyu.edu> <41549A76.221A8526@dessent.net> <Pine.GSO.4.61.0409241804170.20381@slinky.cs.nyu.edu>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-IsSubscribed: yes
Reply-To: cygwin@cygwin.com

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>

> I think Max's solution is probably the least complex short-term one (i.e.,
> run all preremove scripts in batch *before* removing any files, and hope
> for the best).

Yeah, probably true... I realize that people have probably already
suggested these solutions involving graph theory in the past.  And as
you point out, a working patch is one thing, a bunch of conjecture is
another.

Brian

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/