From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Markus Triska Newsgroups: gmane.emacs.bugs Subject: bug#34038: 26.1; set-window-start sometimes fails to set window start Date: Sun, 13 Jan 2019 08:32:44 +0100 Message-ID: <87h8edt3kz.fsf@metalevel.at> References: <83sgxzhe04.fsf@gnu.org> <87ef9je67i.fsf@metalevel.at> <20190111212357.GA5201@ACM> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1547364725 12993 195.159.176.226 (13 Jan 2019 07:32:05 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 13 Jan 2019 07:32:05 +0000 (UTC) User-Agent: Emacs/24.5 Cc: 34038@debbugs.gnu.org To: Alan Mackenzie Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sun Jan 13 08:32:01 2019 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1giaFV-0003Ds-0m for geb-bug-gnu-emacs@m.gmane.org; Sun, 13 Jan 2019 08:32:01 +0100 Original-Received: from localhost ([127.0.0.1]:47612 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1giaHb-0003Aa-Kf for geb-bug-gnu-emacs@m.gmane.org; Sun, 13 Jan 2019 02:34:11 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:39938) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1giaHU-00037F-TN for bug-gnu-emacs@gnu.org; Sun, 13 Jan 2019 02:34:06 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1giaHT-0007gM-5I for bug-gnu-emacs@gnu.org; Sun, 13 Jan 2019 02:34:03 -0500 Original-Received: from debbugs.gnu.org ([209.51.188.43]:58031) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1giaHT-0007fy-1o for bug-gnu-emacs@gnu.org; Sun, 13 Jan 2019 02:34:03 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1giaHS-0002hI-G2 for bug-gnu-emacs@gnu.org; Sun, 13 Jan 2019 02:34:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Markus Triska Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 13 Jan 2019 07:34:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 34038 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 34038-submit@debbugs.gnu.org id=B34038.154736478610299 (code B ref 34038); Sun, 13 Jan 2019 07:34:02 +0000 Original-Received: (at 34038) by debbugs.gnu.org; 13 Jan 2019 07:33:06 +0000 Original-Received: from localhost ([127.0.0.1]:57312 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1giaGX-0002g1-F7 for submit@debbugs.gnu.org; Sun, 13 Jan 2019 02:33:05 -0500 Original-Received: from metalevel.at ([78.46.218.83]:60108) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1giaGE-0002fC-Tv for 34038@debbugs.gnu.org; Sun, 13 Jan 2019 02:33:02 -0500 Original-Received: by metalevel.at (Postfix, from userid 1000) id DB8D7A2AB9; Sun, 13 Jan 2019 08:32:44 +0100 (CET) In-Reply-To: <20190111212357.GA5201@ACM> (Alan Mackenzie's message of "Fri, 11 Jan 2019 21:23:57 +0000") 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: 209.51.188.43 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:154401 Archived-At: Hi Alan, thank you for looking into this, I greatly appreciate it! Alan Mackenzie writes: > . This is pure speculation, but perhaps because the entire buffer is > currently off the screen, with point being on the empty last line, This indeed seems to be a critical factor: an empty last line that appears as the first line of the window. The reason I think that is because if you add for example just a single space to the line, everything works exactly as expected: (progn (goto-char (point-max)) (insert "\n") (dotimes (x (window-height)) (insert (format "%s\n" x))) (insert " ") (backward-char 1) (let ((b (buffer-string)) (p (point))) (redisplay) (set-window-start nil p) (let ((wp (window-point))) (read-key (format "Step 1 at %s wp is %s. Please press a key to continue." (point) wp)) (dotimes (x (round (/ (window-height) 2))) (insert (format "more lines ... %s\n" x))) (read-key (format "Step 2 at %s wp is %s. Please press a key to continue." (point) wp)) (erase-buffer) (insert b) (set-window-point nil wp) (set-window-start nil p)))) Please note the (insert " "). I am using (backward-char 1) to show that the position of point by itself is not enough to trigger the phenomenon. Thank you and all the best! Markus