From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: when do we remove backward compatibility definitions? Date: Tue, 21 Nov 2017 11:54:13 -0800 Organization: UCLA Computer Science Department Message-ID: References: NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1511294102 2545 195.159.176.226 (21 Nov 2017 19:55:02 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 21 Nov 2017 19:55:02 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 To: sds@gnu.org, emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Nov 21 20:54:57 2017 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eHEdC-00005X-M9 for ged-emacs-devel@m.gmane.org; Tue, 21 Nov 2017 20:54:54 +0100 Original-Received: from localhost ([::1]:36278 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eHEdJ-00022G-Vj for ged-emacs-devel@m.gmane.org; Tue, 21 Nov 2017 14:55:02 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:52971) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eHEcg-00022B-0G for emacs-devel@gnu.org; Tue, 21 Nov 2017 14:54:22 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eHEcb-0004lz-3j for emacs-devel@gnu.org; Tue, 21 Nov 2017 14:54:22 -0500 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:46930) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eHEca-0004lC-TO; Tue, 21 Nov 2017 14:54:17 -0500 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 8C6501611EB; Tue, 21 Nov 2017 11:54:14 -0800 (PST) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id yKWdWp9Pej4S; Tue, 21 Nov 2017 11:54:13 -0800 (PST) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 9BCEE1611D6; Tue, 21 Nov 2017 11:54:13 -0800 (PST) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id Gstq3Qov_DcJ; Tue, 21 Nov 2017 11:54:13 -0800 (PST) Original-Received: from Penguin.CS.UCLA.EDU (Penguin.CS.UCLA.EDU [131.179.64.200]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 82CC21610CA; Tue, 21 Nov 2017 11:54:13 -0800 (PST) In-Reply-To: Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 131.179.128.68 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:220334 Archived-At: On 11/21/2017 09:37 AM, Sam Steingold wrote: > What is the policy on removing such declarations? > > R releases? > M major releases? > Y years? > > Where is it officially documented? I don't think we have an official policy, so how about this as a first cut: If the oldest GNU/Linux or other GNU distribution still in reasonably widespread use has Emacs version N, then we don't need to continue to support features that were marked obsolete in version N or earlier. One way to estimate what "reasonably widespread use" means is to look at commercial suppliers and see what they're supporting. If even (say) Red Hat doesn't support an old version of Emacs any more, I would say that the version is so old that we needn't worry about it. With that in mind, currently I would say that Emacs 23.1 is the oldest Emacs we currently need to worry about, since RHEL 6 uses 23.1 and Red Hat plans to keep RHEL 6 in production (which means they'll fix bugs) through 2020-11-30. In contrast, RHEL 5 reached end-of-production on 2017-03-17 so we no longer need to worry about Emacs 21.4, which is what RHEL 5 used. According to this estimate, if a function was marked obsolete in Emacs 23.1 or earlier, we should be able to remove it in the master branch. If not, we should keep it for now. My source for the abovementioned dates is: https://access.redhat.com/support/policy/updates/errata