From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.bugs Subject: bug#33784: 27.0.50; some case c-backward-token-2 takes cpu more and emacs hang Date: Wed, 19 Dec 2018 19:20:08 +0000 Message-ID: <20181219192008.GA5683__32535.2552849383$1545248410$gmane$org@ACM> References: <20181218174716.96822.qmail@mail.muc.de> <83tvjad5x7.fsf@gnu.org> <20181218185505.GC8949@ACM> <83r2eed4fy.fsf@gnu.org> <20181218210507.GD8949@ACM> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1545248410 22651 195.159.176.226 (19 Dec 2018 19:40:10 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 19 Dec 2018 19:40:10 +0000 (UTC) User-Agent: Mutt/1.10.1 (2018-07-13) Cc: 33784@debbugs.gnu.org, linux.xhyang@gmail.com To: Glenn Morris Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Dec 19 20:40:05 2018 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 1gZhhL-0005iQ-8x for geb-bug-gnu-emacs@m.gmane.org; Wed, 19 Dec 2018 20:40:03 +0100 Original-Received: from localhost ([::1]:33881 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZhjS-0003zJ-4i for geb-bug-gnu-emacs@m.gmane.org; Wed, 19 Dec 2018 14:42:14 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:48160) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZhUp-0000Sk-9q for bug-gnu-emacs@gnu.org; Wed, 19 Dec 2018 14:27:08 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gZhUk-0006cI-6a for bug-gnu-emacs@gnu.org; Wed, 19 Dec 2018 14:27:07 -0500 Original-Received: from debbugs.gnu.org ([208.118.235.43]:50841) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gZhUk-0006cA-2O; Wed, 19 Dec 2018 14:27:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1gZhUj-000174-OV; Wed, 19 Dec 2018 14:27:01 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Alan Mackenzie Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org, bug-cc-mode@gnu.org Resent-Date: Wed, 19 Dec 2018 19:27:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 33784 X-GNU-PR-Package: emacs,cc-mode X-GNU-PR-Keywords: Original-Received: via spool by 33784-submit@debbugs.gnu.org id=B33784.15452475884234 (code B ref 33784); Wed, 19 Dec 2018 19:27:01 +0000 Original-Received: (at 33784) by debbugs.gnu.org; 19 Dec 2018 19:26:28 +0000 Original-Received: from localhost ([127.0.0.1]:55099 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gZhUC-00016D-32 for submit@debbugs.gnu.org; Wed, 19 Dec 2018 14:26:28 -0500 Original-Received: from colin.muc.de ([193.149.48.1]:58510 helo=mail.muc.de) by debbugs.gnu.org with smtp (Exim 4.84_2) (envelope-from ) id 1gZhUA-000164-Cc for 33784@debbugs.gnu.org; Wed, 19 Dec 2018 14:26:27 -0500 Original-Received: (qmail 63762 invoked by uid 3782); 19 Dec 2018 19:26:24 -0000 Original-Received: from acm.muc.de (p2E5D5B90.dip0.t-ipconnect.de [46.93.91.144]) by colin.muc.de (tmda-ofmipd) with ESMTP; Wed, 19 Dec 2018 20:26:23 +0100 Original-Received: (qmail 5184 invoked by uid 1000); 19 Dec 2018 19:20:08 -0000 Content-Disposition: inline In-Reply-To: X-Delivery-Agent: TMDA/1.1.12 (Macallan) X-Primary-Address: acm@muc.de 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:153609 Archived-At: Hello, Glenn. On Tue, Dec 18, 2018 at 17:05:22 -0500, Glenn Morris wrote: > > Maybe the solution would be not to start with-temp-buffer names with > > a space. > This sounds totally wrong to me. > > Maybe the documentation for with-temp-buffer should be amended to > > recommend Lisp programmers not to use it for buffers holding user > > text. > This also sounds wrong to me. > I confess I have no idea what problem you are trying to solve here. I have lost the clear overview I had of the problem yesterday, I'm afraid. There is an assemblage of confusing features around this bug which seem to be contributing to the reported bug: (i) A temporary buffer is created and made a C++ Mode buffer. (ii) Font Lock Mode isn't enabled. (iii) Although font lock isn't enabled, font-lock-ensure is called. This hangs. (iv) An attempt to enable Font Lock Mode on this buffer fails silently, because the buffer name begins with a space. (v) It is unclear whether font-lock-ensure is intended to work when Font Lock Mode is disabled. (vi) The spiking of Font Lock Mode to fail on "space buffers" is not documented, and 23 years later, the reason for it is obscure. Hope that helps, if only a little. -- Alan Mackenzie (Nuremberg, Germany).