From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: A solution to display completion candidates after point in a minibuffer Date: Sun, 04 Oct 2020 19:21:51 +0300 Message-ID: <83o8lidkrk.fsf@gnu.org> References: <83sgavfzno.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="33104"; mail-complaints-to="usenet@ciao.gmane.io" Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org To: Gregory Heytings Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sun Oct 04 18:23:25 2020 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 1kP6nE-0008TV-Dk for ged-emacs-devel@m.gmane-mx.org; Sun, 04 Oct 2020 18:23:24 +0200 Original-Received: from localhost ([::1]:58800 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kP6nD-0007ig-Ca for ged-emacs-devel@m.gmane-mx.org; Sun, 04 Oct 2020 12:23:23 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:58824) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kP6ln-0007Bc-9L for emacs-devel@gnu.org; Sun, 04 Oct 2020 12:21:55 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:43286) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kP6lk-0004up-Eh; Sun, 04 Oct 2020 12:21:52 -0400 Original-Received: from [176.228.60.248] (port=1762 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1kP6lj-0004Ha-OK; Sun, 04 Oct 2020 12:21:52 -0400 In-Reply-To: (message from Gregory Heytings on Sun, 04 Oct 2020 16:11:06 +0000) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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:257035 Archived-At: > Date: Sun, 04 Oct 2020 16:11:06 +0000 > From: Gregory Heytings > cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org > > > No, redisplay will never accept a result that point is invisible. If it > > ever does display such situations, it's a bug that needs to be fixed. > > Never say never... > > >> It becomes visible again after the next redisplay, a second or two > >> later. > > > > If such a situation exists, please describe how to reproduce it, because > > it's a bug we need to fix. Emacs should never display a window where > > point is not fully visible. > > > > Here's a recipe: > > emacs -Q > (defun recipe () > (interactive) > (set-frame-width nil 80) > (set-frame-height nil 30) > (switch-to-buffer (get-buffer-create "*Recipe*")) > (goto-char 1) > (let ((i 0)) (while (< i 60) (setq i (1+ i)) (insert (format "L%d\n" i)))) > (goto-char 148) > (sit-for 0.25) > (add-hook 'window-scroll-functions (lambda (&rest args) (set-window-start nil 1))) > (forward-line 13)) > M-x recipe > press C-n AFAIU, this is exactly why we say not to use window-scroll-functions for this purpose. IOW, there is indeed a bug here, and the bug is in the Lisp code you presented: window-scroll-functions are not meant to be used to affect redisplay, they are meant to inform Lisp programs about what redisplay is about to do with a window.