From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: charles@aurox.ch (Charles A. Roelli) Newsgroups: gmane.emacs.bugs Subject: bug#29325: 26.0.90: Info scrolling stuck Date: Mon, 20 Nov 2017 20:52:39 +0100 Message-ID: References: <83fu9ehuog.fsf@gnu.org> <83d14hidlk.fsf@gnu.org> <83r2sudwgv.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1511207533 7183 195.159.176.226 (20 Nov 2017 19:52:13 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 20 Nov 2017 19:52:13 +0000 (UTC) Cc: 29325@debbugs.gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Mon Nov 20 20:52:07 2017 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1eGs6u-0001NA-7i for geb-bug-gnu-emacs@m.gmane.org; Mon, 20 Nov 2017 20:52:04 +0100 Original-Received: from localhost ([::1]:59432 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eGs71-0002Er-NA for geb-bug-gnu-emacs@m.gmane.org; Mon, 20 Nov 2017 14:52:11 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:58000) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eGs6v-0002EP-GS for bug-gnu-emacs@gnu.org; Mon, 20 Nov 2017 14:52:06 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eGs6s-0007cc-E9 for bug-gnu-emacs@gnu.org; Mon, 20 Nov 2017 14:52:05 -0500 Original-Received: from debbugs.gnu.org ([208.118.235.43]:40776) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1eGs6s-0007cR-AT for bug-gnu-emacs@gnu.org; Mon, 20 Nov 2017 14:52:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1eGs6s-0001PH-4S for bug-gnu-emacs@gnu.org; Mon, 20 Nov 2017 14:52:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: charles@aurox.ch (Charles A. Roelli) Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 20 Nov 2017 19:52:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 29325 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 29325-submit@debbugs.gnu.org id=B29325.15112075055382 (code B ref 29325); Mon, 20 Nov 2017 19:52:02 +0000 Original-Received: (at 29325) by debbugs.gnu.org; 20 Nov 2017 19:51:45 +0000 Original-Received: from localhost ([127.0.0.1]:49457 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eGs6b-0001Ok-6w for submit@debbugs.gnu.org; Mon, 20 Nov 2017 14:51:45 -0500 Original-Received: from sinyavsky.aurox.ch ([37.35.109.145]:49256) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eGs6Z-0001OY-Dm for 29325@debbugs.gnu.org; Mon, 20 Nov 2017 14:51:43 -0500 Original-Received: from sinyavsky.aurox.ch (sinyavsky.aurox.ch [127.0.0.1]) by sinyavsky.aurox.ch (Postfix) with ESMTP id ED6D1225CC for <29325@debbugs.gnu.org>; Mon, 20 Nov 2017 19:44:21 +0000 (UTC) Authentication-Results: sinyavsky.aurox.ch (amavisd-new); dkim=pass (1024-bit key) reason="pass (just generated, assumed good)" header.d=aurox.ch DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=aurox.ch; h= references:subject:subject:in-reply-to:to:from:from:message-id :date:date; s=dkim; t=1511207060; x=1512071061; bh=oUykwlh3Ec+BZ x5O0INsfjdioy+5kztzub6wSW7zGqA=; b=pVLsgE3zH9VFyObWj2BvSyhaYvYyp 7x0HAh8t76aogkqZ32h/QxEOlTCWTmi/LWYTLuQBy1UXaPpzd+5/VShwyOPyAiQJ Gn6HaaDF38ieYTDZhx0Lv2cHQU50SS8RrGfrtGH8ch3S771aFo1NjURBnpZIe5Rs mowyWl836nnqIk= X-Virus-Scanned: Debian amavisd-new at test.virtualizor.com Original-Received: from sinyavsky.aurox.ch ([127.0.0.1]) by sinyavsky.aurox.ch (sinyavsky.aurox.ch [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id LpHisusUMFSv for <29325@debbugs.gnu.org>; Mon, 20 Nov 2017 19:44:20 +0000 (UTC) Original-Received: from gray (125.85.192.178.dynamic.wline.res.cust.swisscom.ch [178.192.85.125]) by sinyavsky.aurox.ch (Postfix) with ESMTPSA id 69E64225C1; Mon, 20 Nov 2017 19:44:20 +0000 (UTC) In-reply-to: <83r2sudwgv.fsf@gnu.org> (message from Eli Zaretskii on Sun, 19 Nov 2017 19:12:00 +0200) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:140164 Archived-At: > Date: Sun, 19 Nov 2017 19:12:00 +0200 > From: Eli Zaretskii > > > > Does the same problem happen if you scroll with "M-1 M-v" instead of > > > the mouse wheel? > > > > No: it works fine in that case. > > If this is only about scrolling with the mouse wheel, then perhaps the > factor which differs between our systems is the amount of scrolling > per wheel notch. How many lines does a single notch scroll in your > case? And does the problem happen if you turn the wheel slowly? I don't have access to a GNU/Linux system at the moment, but if I recall correctly, it would be 5 lines at a time, when scrolling slowly. The behavior is different depending on how fast the mouse wheel is turned. If it is turned slowly several times in a row, it is possible to make window-start reach as far as the second or third line of the buffer. If you turn it once more, then window-start jerks down a few lines instead of reaching the start of the buffer. This can be repeated ad infinitum. In contrast, when turning the mouse wheel quickly (a few notches in one second), it is not possible to get window-start anywhere near the start of the buffer, except by using non-mouse commands or by setting point closer to the top of the window first (with the mouse). > > > (cond ((eq button mouse-wheel-down-event) > > > (condition-case nil (funcall mwheel-scroll-down-function amt) > > > ;; Make sure we do indeed scroll to the beginning of > > > ;; the buffer. > > > (beginning-of-buffer > > > (unwind-protect > > > (funcall mwheel-scroll-down-function) > > > ;; If the first scroll succeeded, then some scrolling > > > ;; is possible: keep scrolling til the beginning but > > > ;; do not signal an error. For some reason, we have > > > ;; to do it even if the first scroll signaled an > > > ;; error, because otherwise the window is recentered > > > ;; for a reason that escapes me. This problem seems > > > ;; to only affect scroll-down. --Stef > > > (set-window-start (selected-window) (point-min)))))) > > > > That is, when attempting to scroll down (as in, moving towards > > beginning of buffer) under some mysterious circumstances, the window > > gets recentered around point instead of being scrolled. However, if > > point is moved to the first line of the window, say, then the > > scrolling does work as expected (as I've found out by experimenting > > more with my initial recipe). > > I have serious difficulties dealing with unexplained and undescribed > problems that happen "under mysterious circumstances". > > If you build with --enable-checking='yes,glyphs', and then turn on > redisplay tracing with "M-x trace-redisplay" before scrolling with the > wheel, what do you see? And how does that trace differ from when you > scroll with "M-1 M-v"? Thanks, I will try that soon. In the meantime, I noticed that I could also reproduce the bug in Emacs 25.2, but not in 25.1. I will try to bisect between the releases. > (I find it useful to disable blink-cursor-mode and global-eldoc-mode > before such experiments, because they tend to trigger extra redisplay > cycles that conceal the interesting parts.)