From owner-freebsd-hackers@FreeBSD.ORG  Fri Nov  9 03:40:03 2007
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 4B85A16A421
	for <hackers@freebsd.org>; Fri,  9 Nov 2007 03:40:03 +0000 (UTC)
	(envelope-from mwm@mired.org)
Received: from mired.org (bhuda.mired.org [66.92.153.74])
	by mx1.freebsd.org (Postfix) with SMTP id AC44513C494
	for <hackers@freebsd.org>; Fri,  9 Nov 2007 03:40:02 +0000 (UTC)
	(envelope-from mwm@mired.org)
Received: (qmail 73982 invoked from network); 6 Nov 2007 16:53:16 -0000
Received: from unknown (HELO mbook.mired.org) (192.168.195.2)
	by 0 with SMTP; 6 Nov 2007 16:53:16 -0000
Date: Tue, 6 Nov 2007 11:52:52 -0500
From: Mike Meyer <mwm@mired.org>
To: "Julian H. Stacey" <jhs@berklix.org>
Message-ID: <20071106115252.1f97af6d@mbook.mired.org>
In-Reply-To: <200711061620.lA6GKE8L090019@fire.js.berklix.net>
References: <200711050002.lA502KUe064392@fire.js.berklix.net>
	<20071105085259.A39496@knop-beagle.kn.op.dlr.de>
	<200711061620.lA6GKE8L090019@fire.js.berklix.net>
Organization: Meyer Consulting
X-Mailer: Claws Mail 2.10.0 (GTK+ 2.6.10; i386-apple-darwin8.10.1)
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
X-Mailman-Approved-At: Fri, 09 Nov 2007 03:55:21 +0000
Cc: hackers@freebsd.org, Harti Brandt <harti@freebsd.org>
Subject: Re: make: evaluation of symbolic link with ../ fails
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 09 Nov 2007 03:40:03 -0000

On Tue, 06 Nov 2007 17:20:14 +0100 "Julian H. Stacey" <jhs@berklix.org> wrote:
> It seems to me that all except csh (including bourne shell !) are
> broken !! Amazing ! None of them cope properly actually following
> symbolic links, they all make false premise the /some_path/.. ==
> /some_path !

That's not a bug, that's a feature. When symlinks were introduced in
4.1c (or thereabouts), people were often surprised to do:

$ cd /some_path/child
$ ...
$ cd ..

and not wind up in /some_path, or having the ever popular sh loop:

$ for dir in <list of subdirs>
$ do
$   cd $dir
$   ...
$   cd ..
$ done

start working on something totally unrelated to the current directory
halfway through the loop. So sh (and etc.) added a feature so that
those things worked the way users expected them to.

Basically, the shells don't make a false premise that /some_path/.. ==
/some_path, they make the premise appear to be true as a feature.

      <mike
-- 
Mike Meyer <mwm@mired.org>		http://www.mired.org/consulting.html
Independent Network/Unix/Perforce consultant, email for more information.