From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: moving SCCS later in vc-handled-backends Date: Wed, 24 Jun 2009 23:41:25 +0200 Message-ID: References: <200906230701.n5N71kIi007475@godzilla.ics.uci.edu> <877hz3z6z0.fsf@uwakimon.sk.tsukuba.ac.jp> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1245879755 8301 80.91.229.12 (24 Jun 2009 21:42:35 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 24 Jun 2009 21:42:35 +0000 (UTC) Cc: Dan Nicolaescu , emacs-devel@gnu.org To: "Stephen J. Turnbull" Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Jun 24 23:42:28 2009 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1MJaEd-0002Af-RE for ged-emacs-devel@m.gmane.org; Wed, 24 Jun 2009 23:42:28 +0200 Original-Received: from localhost ([127.0.0.1]:53711 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MJaEd-0004GI-Ac for ged-emacs-devel@m.gmane.org; Wed, 24 Jun 2009 17:42:27 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MJaDh-0003fE-Mt for emacs-devel@gnu.org; Wed, 24 Jun 2009 17:41:29 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MJaDd-0003aj-55 for emacs-devel@gnu.org; Wed, 24 Jun 2009 17:41:29 -0400 Original-Received: from [199.232.76.173] (port=47782 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MJaDd-0003ac-07 for emacs-devel@gnu.org; Wed, 24 Jun 2009 17:41:25 -0400 Original-Received: from smtp-01.vtx.ch ([212.147.0.84]:43053) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MJaDc-0006gp-Im for emacs-devel@gnu.org; Wed, 24 Jun 2009 17:41:24 -0400 Original-Received: from alfajor.home (dyn.83-228-166-055.dsl.vtx.ch [83.228.166.55]) by smtp-01.vtx.ch (VTX Services SA) with ESMTP id D98172809A; Wed, 24 Jun 2009 23:41:23 +0200 (CEST) Original-Received: by alfajor.home (Postfix, from userid 20848) id 37B5964345; Wed, 24 Jun 2009 23:41:25 +0200 (CEST) In-Reply-To: <877hz3z6z0.fsf@uwakimon.sk.tsukuba.ac.jp> (Stephen J. Turnbull's message of "Tue, 23 Jun 2009 17:31:47 +0900") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.94 (gnu/linux) X-detected-operating-system: by monty-python.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:111696 Archived-At: >> When opening any version controlled file that is under one of the more >> modern VCs, SCCS is tried first. >> Given that it's not a popular system, this is pure overhead, >> so it would be better move it at the end of vc-handled-backends. >> Any objection to this change: > Yes. This change is backward incompatible and buggy; the rationale > for SCCS being in the "early" group still holds as far as I know, > unless SCCS has improved its support for whole-tree commits recently. 100% agreement. For any non-VC files, the whole list will be traversed anyway, so the order doesn't make much difference (if any) in terms of performance. If we change ordering, it should not be for performance reasons (unless you can actually show some hard-data demonstrating the positive effects in realistic scenarios). We could consider removing elements from the list based on the presence/absence of the necessary tools on the system (tho it might not be such a great idea either, since for many backends, the tools are not necessary to find the backend and the current revision and state, and also because many backends can be used via Tramp). Stefan