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: Edebug corrupting point in buffers. Date: Tue, 1 Nov 2022 17:06:38 +0000 Message-ID: References: <83wn8fcgvd.fsf@gnu.org> <83iljydh7e.fsf@gnu.org> <838rkud9d5.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="3196"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Nov 01 18:26:25 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 1opv1s-0000Ko-RR for ged-emacs-devel@m.gmane-mx.org; Tue, 01 Nov 2022 18:26:24 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1opuix-0001MQ-6H; Tue, 01 Nov 2022 13:06:51 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1opuir-00014i-Fd for emacs-devel@gnu.org; Tue, 01 Nov 2022 13:06:46 -0400 Original-Received: from mx3.muc.de ([193.149.48.5]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1opuip-0000M5-H5 for emacs-devel@gnu.org; Tue, 01 Nov 2022 13:06:45 -0400 Original-Received: (qmail 3152 invoked by uid 3782); 1 Nov 2022 18:06:40 +0100 Original-Received: from acm.muc.de (p4fe15c46.dip0.t-ipconnect.de [79.225.92.70]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Tue, 01 Nov 2022 18:06:39 +0100 Original-Received: (qmail 7788 invoked by uid 1000); 1 Nov 2022 17:06:38 -0000 Content-Disposition: inline In-Reply-To: <838rkud9d5.fsf@gnu.org> X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de Received-SPF: pass client-ip=193.149.48.5; envelope-from=acm@muc.de; helo=mx3.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 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: , Original-Sender: "Emacs-devel" Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:298958 Archived-At: Hello, Eli. On Tue, Nov 01, 2022 at 16:42:30 +0200, Eli Zaretskii wrote: > > Date: Tue, 1 Nov 2022 13:42:03 +0000 > > Cc: emacs-devel@gnu.org > > From: Alan Mackenzie > > > ??? Why would point be restored to the value before the last move of > > > point? The program you are debugging doesn't affect that buffer with > > > notes, does it? > > Probably not, but it might. The point is, edebug can't know [*] which > > buffers have been modified by edebug itself, and which have been modified > > by the user. Some might have been modified by both. > > [*] Without significant enhancement to edebug. > What do you mean by "buffers modified by edebug itself"? AFAIK, > Edebug doesn't modify any buffers except the one where you are > stepping, where it moves the overlay arrow and point. Sorry, can we pretend I didn't write that last paragraph, please? It's nonsense. Going back to your question three paragraphs ago, which I haven't answered yet, point in the notes buffer would get restored by the window configuration stuff we're discussing below. At least it would if it's displayed in the selected frame. > > > > With test-edebug.el being > > > > ######################################################################### > > > > 1 (defun test-edebug () > > > > 2 (let ((A "*scratch*") (B "emacs.README")) > > > > 3 (set-buffer A) > > > > 4 (set-buffer B) > > > > 5 (goto-char (point-max)) > > > > 6 (insert "(2022-11-01)\n") > > > > 7 ;; B's buffer-point is at point-max. > > > > 8 > > > > 9 (set-buffer A) > > > > 10 (set-buffer B) > > > > 11 ;; B's buffer-point is no longer at point-max. > > > > 12 (insert "(2022-11-01)a\n"))) > > > > ######################################################################### > > > > , > > > > (i) Emacs -Q. > > > > (ii) On a single frame, arrange buffers *scratch*, test-edebug.el, and > > > > some other substantial buffer, that I call emacs.README. > > > > (iii) Put point in emacs.README somewhere other than point-max. > > > > (iv) Instrument test-edebug for edebug with C-u C-M-x. > > > > (v) M-: (test-edebug). > > > > (vi) Step through test-edebug using the space key. > > > > (vii) Note that the second text insertion happens where point was in the > > > > window, not at point-max. This is the bug. > > > I cannot reproduce this: for me, the insertion is at point-max. Maybe > > > your recipe description is incomplete? > > Apologies. I neglected to mention that window-saving (toggled by "W" in > > an edebug session) must be enabled to trigger the bug. Indeed, I wasn't > > fully aware of this. > If the problem happens only when edebug-save-displayed-buffer-points > is non-nil, then maybe we should step back a notch and ask why you set > that option? It is nil by default. It is t by default, and has been since Richard S. created or amended the declaration in 1997. It frequently annoys me when I go into edebug (but not enough for me actually to customise it to nil). > What doesn't work for you if you keep it at its nil value? Before I got into the habit of typing W to set it to nil, I seem to remember that sometimes my .el buffer would scroll back to its previous position when I typed (edebug's) space, sometimes it wouldn't. I never worked out why. Might you have customised it to nil in your own configuration? > AFAIU, this variable exists for some very special situations (which > ones exactly I admit I don't have a clear idea), and it could be that > your use case is not one of them. As I say, I just find it annoying. But t is the default value for it, for reasons probably long lost. -- Alan Mackenzie (Nuremberg, Germany).