From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: What's happened to M- `completion-at-point'? Date: Thu, 5 May 2022 16:57:55 +0000 Message-ID: References: <83sfpp2qvy.fsf@gnu.org> <83r1592km7.fsf@gnu.org> <83fslo33ha.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="37248"; mail-complaints-to="usenet@ciao.gmane.io" Cc: yuri.v.khan@gmail.com, monnier@iro.umontreal.ca, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Thu May 05 19:05:52 2022 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nmevI-0009We-8z for ged-emacs-devel@m.gmane-mx.org; Thu, 05 May 2022 19:05:52 +0200 Original-Received: from localhost ([::1]:51264 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nmevH-00072W-2y for ged-emacs-devel@m.gmane-mx.org; Thu, 05 May 2022 13:05:51 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:49006) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nmeni-0006ux-04 for emacs-devel@gnu.org; Thu, 05 May 2022 12:58:03 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:65282 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.90_1) (envelope-from ) id 1nmend-0007M2-SW for emacs-devel@gnu.org; Thu, 05 May 2022 12:58:00 -0400 Original-Received: (qmail 73965 invoked by uid 3782); 5 May 2022 16:57:55 -0000 Original-Received: from acm.muc.de (p4fe15ab6.dip0.t-ipconnect.de [79.225.90.182]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Thu, 05 May 2022 18:57:55 +0200 Original-Received: (qmail 12471 invoked by uid 1000); 5 May 2022 16:57:55 -0000 Content-Disposition: inline In-Reply-To: <83fslo33ha.fsf@gnu.org> X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de Received-SPF: pass client-ip=193.149.48.1; envelope-from=acm@muc.de; helo=mail.muc.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:289253 Archived-At: Hello, Eli. On Thu, May 05, 2022 at 09:20:17 +0300, Eli Zaretskii wrote: > > Date: Wed, 4 May 2022 21:07:04 +0000 > > Cc: Stefan Monnier , Eli Zaretskii , > > Emacs developers > > From: Alan Mackenzie > > Maybe the best thing we can do in Emacs is to remove that entry for "kB" > > in src/term.c. That would prevent Emacs recognising TAB on all > > these misconfigured keyboards. I think that is a lesser evil than > > failing to recognise TAB. > This doesn't sound like a good idea to me. Emacs shouldn't try > second-guessing the user's keyboard configuration, it isn't in our > mandate. We have a bug here, Emacs does not work properly. While it is true in theory that a user might be able to fix it in her configuration, in practice this is just too difficult for a user to diagnose and fix. Note that all the key sequences M-tab, ESC TAB, and C-M-i are affected. The change from ncurses-6.2 to ncurses-6.3 broke the Linux console keyboard, in that terminfo now directs ESC TAB to be translated to backtab. This was almost certainly intentional, possibly prompted by the misconfiguration of so many Linux keyboard layouts (in /usr/share/keymaps/...), where the TAB key sequence produces the characters ESC TAB. I can imagine that there was a lot of strenuous discussion on the ncurses mailing list before making this change, and that it was done with regret. > If the terminfo database you have doesn't do what you want, why can't > you modify it? The tools to do that are available, and aren't part of > Emacs. I could do this without too much difficulty for myself personally, but that doesn't fix the bug for other users. I don't think we want to distribute a version of terminfo just for Linux Emacs users. > (We could include the instructions for making such a change in > PROBLEMS, if this is a common issue.) Of course, the best solution > would be if the distro changes the terminfo database. There are many GNU/Linux distros all distributing Emacs, and I think it likely that few, if any, will be prepared to fix terminfo (likely "breaking" other programs) for the sake of Emacs. Our problem here is caused by an ad hoc change to terminfo. Why can't we fix it likewise by an ad hoc change in Emacs, that would prevent ESC TAB only on the Linux keyboard from being changed into backtab. We could make this optional, either by a run-time or a configure-time option. -- Alan Mackenzie (Nuremberg, Germany).