From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: =?utf-8?Q?=C3=93scar_Fuentes?= Newsgroups: gmane.emacs.help Subject: Re: Reverting but keeping undo Date: Thu, 30 May 2013 21:19:41 +0200 Message-ID: <877giguvg2.fsf@wanadoo.es> References: <87mwrwede7.fsf@wanadoo.es> <878v2w8g3t.fsf@web.de> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1369941621 6506 80.91.229.3 (30 May 2013 19:20:21 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 30 May 2013 19:20:21 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Thu May 30 21:20:20 2013 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Ui8Oa-00015O-7v for geh-help-gnu-emacs@m.gmane.org; Thu, 30 May 2013 21:20:20 +0200 Original-Received: from localhost ([::1]:58937 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ui8OZ-0007eS-RA for geh-help-gnu-emacs@m.gmane.org; Thu, 30 May 2013 15:20:19 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:35735) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ui8OI-0007Zn-CV for help-gnu-emacs@gnu.org; Thu, 30 May 2013 15:20:10 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ui8OA-0006Ii-QI for help-gnu-emacs@gnu.org; Thu, 30 May 2013 15:20:02 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:59778) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ui8OA-0006IU-Jj for help-gnu-emacs@gnu.org; Thu, 30 May 2013 15:19:54 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1Ui8O9-0000l4-24 for help-gnu-emacs@gnu.org; Thu, 30 May 2013 21:19:53 +0200 Original-Received: from 237.red-83-43-53.dynamicip.rima-tde.net ([83.43.53.237]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 30 May 2013 21:19:53 +0200 Original-Received: from ofv by 237.red-83-43-53.dynamicip.rima-tde.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 30 May 2013 21:19:53 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 28 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 237.red-83-43-53.dynamicip.rima-tde.net User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) Cancel-Lock: sha1:FEvGa74oC1N9zxMRMHy6e0JTHaI= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:91181 Archived-At: Michael Heerdegen writes: >> FWIW, I just installed a patch in Emacs's trunk which makes that >> revert-buffer doesn't discard undo history any more. > > I wonder how that works. Generally, the undo history belongs to a > buffer content different from the content after reverting. Does your > patch prevent surprises like "undoing" changes that were never made to > the newly read-in buffer content? I have not tried the change introduced by Stefan, so my comments below are just hypothetical. Keeping undo history makes a lot of sense on this scenario: 1 Visit file 2 Edit 3 Save 3 Edit 4 Revert It is obvious that the undo history created by step 3 is unusable, but the part created by step 2 is useful. Until now, Emacs discardeded all undo history. What happens when the file is modified outside of Emacs? You migth end with elements in the undo history which are out of sync with the file contents. I don't know how Emacs behaves on those situations.