From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#9642: move-overlay creates an empty overlay with the evaporate property Date: Sat, 01 Oct 2011 11:22:55 +0300 Message-ID: <83hb3tce8w.fsf@gnu.org> References: <4E8648C6.5050905@cs.ucla.edu> <4E86C25D.5010108@cs.ucla.edu> Reply-To: Eli Zaretskii NNTP-Posting-Host: lo.gmane.org X-Trace: dough.gmane.org 1317457440 19568 80.91.229.12 (1 Oct 2011 08:24:00 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Sat, 1 Oct 2011 08:24:00 +0000 (UTC) Cc: 9642@debbugs.gnu.org To: Paul Eggert Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sat Oct 01 10:23:56 2011 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1R9urT-00050b-VY for geb-bug-gnu-emacs@m.gmane.org; Sat, 01 Oct 2011 10:23:56 +0200 Original-Received: from localhost ([::1]:57876 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R9urT-0002eT-6S for geb-bug-gnu-emacs@m.gmane.org; Sat, 01 Oct 2011 04:23:55 -0400 Original-Received: from eggs.gnu.org ([140.186.70.92]:34005) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R9urQ-0002eJ-Pt for bug-gnu-emacs@gnu.org; Sat, 01 Oct 2011 04:23:53 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R9urP-0000pi-Oz for bug-gnu-emacs@gnu.org; Sat, 01 Oct 2011 04:23:52 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:39047) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R9urP-0000pe-MD for bug-gnu-emacs@gnu.org; Sat, 01 Oct 2011 04:23:51 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.69) (envelope-from ) id 1R9usY-00076m-4v for bug-gnu-emacs@gnu.org; Sat, 01 Oct 2011 04:25:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sat, 01 Oct 2011 08:25:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 9642 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: patch Original-Received: via spool by 9642-submit@debbugs.gnu.org id=B9642.131745746127275 (code B ref 9642); Sat, 01 Oct 2011 08:25:02 +0000 Original-Received: (at 9642) by debbugs.gnu.org; 1 Oct 2011 08:24:21 +0000 Original-Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1R9urs-00075r-W3 for submit@debbugs.gnu.org; Sat, 01 Oct 2011 04:24:21 -0400 Original-Received: from mtaout23.012.net.il ([80.179.55.175]) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1R9urp-00075j-Uk for 9642@debbugs.gnu.org; Sat, 01 Oct 2011 04:24:19 -0400 Original-Received: from conversion-daemon.a-mtaout23.012.net.il by a-mtaout23.012.net.il (HyperSendmail v2007.08) id <0LSD00100OBMT800@a-mtaout23.012.net.il> for 9642@debbugs.gnu.org; Sat, 01 Oct 2011 11:22:52 +0300 (IDT) Original-Received: from HOME-C4E4A596F7 ([84.228.74.35]) by a-mtaout23.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0LSD002QOOM3KG10@a-mtaout23.012.net.il>; Sat, 01 Oct 2011 11:22:52 +0300 (IDT) In-reply-to: <4E86C25D.5010108@cs.ucla.edu> X-012-Sender: halo1@inter.net.il X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list Resent-Date: Sat, 01 Oct 2011 04:25:02 -0400 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 1) X-Received-From: 140.186.70.43 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-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:52028 Archived-At: > Date: Sat, 01 Oct 2011 00:33:49 -0700 > From: Paul Eggert > Cc: 9642@debbugs.gnu.org > > On 09/30/11 21:01, Stefan Monnier wrote: > > > if the user goes through the trouble to do the above, he probably > > doesn't want this overlay to disappear right away > > I don't see why not. Evaporating overlays are supposed > disappear when they become empty -- that's their whole point. > Why would one want an evaporating overflow that's empty? But what is the meaning of moving an overlay to begin at buffer position zero? Such a position doesn't exist in any buffer. So doing this invokes undefined behavior, whose result can be anything, including the end of the world. > Let's look at it a different way. Suppose we were to try > to document the current behavior. We'd add something to > the manual like "overlays with the evaporate property are deleted when > they become empty, except when X". What would X be, X == "empty means the beginning and the end positions of the overlay are identical".