From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Toby Cubitt Newsgroups: gmane.emacs.bugs Subject: bug#24640: Crashes in 25.1 Date: Wed, 12 Oct 2016 19:07:26 +0100 Message-ID: <20161012180726.GA6818@marvin.cs.ucl.ac.uk> References: NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1476295828 28809 195.159.176.226 (12 Oct 2016 18:10:28 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 12 Oct 2016 18:10:28 +0000 (UTC) User-Agent: Mutt/1.5.24 (2015-08-30) Cc: 24640@debbugs.gnu.org, phillip.lord@russet.org.uk, rrt@sc3d.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Oct 12 20:10:24 2016 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 1buNyp-0005z3-6J for geb-bug-gnu-emacs@m.gmane.org; Wed, 12 Oct 2016 20:10:15 +0200 Original-Received: from localhost ([::1]:35058 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buNyn-00053A-Qo for geb-bug-gnu-emacs@m.gmane.org; Wed, 12 Oct 2016 14:10:13 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:39276) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buNyh-00051P-BQ for bug-gnu-emacs@gnu.org; Wed, 12 Oct 2016 14:10:08 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1buNyc-0001KU-FA for bug-gnu-emacs@gnu.org; Wed, 12 Oct 2016 14:10:06 -0400 Original-Received: from debbugs.gnu.org ([208.118.235.43]:47143) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buNyc-0001KM-Bm for bug-gnu-emacs@gnu.org; Wed, 12 Oct 2016 14:10:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1buNyc-0005Y9-2T for bug-gnu-emacs@gnu.org; Wed, 12 Oct 2016 14:10:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Toby Cubitt Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 12 Oct 2016 18:10:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 24640 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 24640-submit@debbugs.gnu.org id=B24640.147629576921281 (code B ref 24640); Wed, 12 Oct 2016 18:10:02 +0000 Original-Received: (at 24640) by debbugs.gnu.org; 12 Oct 2016 18:09:29 +0000 Original-Received: from localhost ([127.0.0.1]:53333 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1buNy0-0005X7-OU for submit@debbugs.gnu.org; Wed, 12 Oct 2016 14:09:28 -0400 Original-Received: from sanddollar.geekisp.com ([216.168.135.167]:18947) by debbugs.gnu.org with smtp (Exim 4.84_2) (envelope-from ) id 1buNxz-0005Wu-NH for 24640@debbugs.gnu.org; Wed, 12 Oct 2016 14:09:24 -0400 Original-Received: (qmail 22222 invoked by uid 1003); 12 Oct 2016 18:04:12 -0000 Original-Received: from marvin.localdomain (localhost.geekisp.com [127.0.0.1]) by localhost.geekisp.com (tmda-ofmipd) with ESMTP; Wed, 12 Oct 2016 14:04:08 -0400 Original-Received: by marvin.localdomain (Postfix, from userid 1000) id C53B212151FE; Wed, 12 Oct 2016 19:07:26 +0100 (BST) Content-Disposition: inline In-Reply-To: <83k2dda33k.fsf@gnu.org> X-PGP-Key: http://www.dr-qubit.org/gpg-toby-pub.asc X-Delivery-Agent: TMDA/1.1.11 (Ladyburn) X-Primary-Address: toby@dr-qubit.org 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:124411 Archived-At: On Wed, Oct 12, 2016 at 08:28:47PM +0300, Eli Zaretskii wrote: > > Date: Wed, 12 Oct 2016 17:56:56 +0100 > > Cc: phillip.lord@russet.org.uk, rrt@sc3d.org, 24640@debbugs.gnu.org > > From: Toby Cubitt > > > > > Does restoring undo-tree history manipulates buffer-undo-list of any > > > buffers in any way? > > > > No. It just reads a lisp structure from file into the buffer-undo-tree > > variable. > > In that case, changes in Emacs undo internals are probably off the > hook. Hmm... which leaves us with what other suspects? Does loading Reuben's history file using undo-tree-load-history starting from emacs -Q trigger the crash? From the discussion, I'm guessing not... > Well, one place where redisplay could be triggered is those messages > about failure to load history, like this one (which actually happens > during restoring Emacs sessions from Reuben's desktop file): > > Error reading undo-tree history from "/home/user/.emacs.d/undo-tree/.!home!user!Foo!Bar!baz!doc!yyy.tex.~undo-tree~" > > (I obfuscated a few directory names here to protect Reuben's privacy.) That's odd. That particular error message can only be triggered if one of the two (read (current-buffer)) calls fails. It means the undo history file exists, but `read' could not parse the contents into a lisp expression (or errored for some other reason). This shouldn't be possible. Undo-tree uses `prin1` to write one hash and one complicated lisp structure to the file when it saves history. The lisp structure does have a read syntax. Unless the history file has been modified outside of undo-tree, it should always be able to read these back in. Normal situations, like failing to find an undo history file or detecting that the file has changed since the history was written, trigger different error messages. Maybe this is a red herring, since failing to read a lisp expression shouldn't crash Emacs anyway. But it's odd to me that this message is triggered at all... T. -- Dr T. S. Cubitt Royal Society University Research Fellow Quantum Information Theory Department of Computer Science University College London email: tsc25@cantab.net web: www.dr-qubit.org