From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Removing rollback from VC mode - request for comment Date: Thu, 11 Dec 2014 20:30:58 +0200 Message-ID: <83sigmrqcd.fsf@gnu.org> References: <20141211092138.6D5F6C008E@snark.thyrsus.com> <874mt2iksu.fsf@fencepost.gnu.org> <87fvcm8jf0.fsf@zigzag.favinet> <20141211125145.GB25499@thyrsus.com> <83d27qtar6.fsf@gnu.org> <20141211174508.GC581@thyrsus.com> Reply-To: Eli Zaretskii NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1418322692 4205 80.91.229.3 (11 Dec 2014 18:31:32 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 11 Dec 2014 18:31:32 +0000 (UTC) Cc: emacs-devel@gnu.org To: esr@thyrsus.com Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Dec 11 19:31:25 2014 Return-path: Envelope-to: ged-emacs-devel@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 1Xz8WK-0007hM-N5 for ged-emacs-devel@m.gmane.org; Thu, 11 Dec 2014 19:31:24 +0100 Original-Received: from localhost ([::1]:53085 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xz8WK-0001KD-A2 for ged-emacs-devel@m.gmane.org; Thu, 11 Dec 2014 13:31:24 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:57730) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xz8W2-0001K7-DF for emacs-devel@gnu.org; Thu, 11 Dec 2014 13:31:11 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xz8Vw-0008Vj-SY for emacs-devel@gnu.org; Thu, 11 Dec 2014 13:31:06 -0500 Original-Received: from mtaout24.012.net.il ([80.179.55.180]:59734) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xz8Vw-0008VQ-KC for emacs-devel@gnu.org; Thu, 11 Dec 2014 13:31:00 -0500 Original-Received: from conversion-daemon.mtaout24.012.net.il by mtaout24.012.net.il (HyperSendmail v2007.08) id <0NGF00500K9N6Q00@mtaout24.012.net.il> for emacs-devel@gnu.org; Thu, 11 Dec 2014 20:23:11 +0200 (IST) Original-Received: from HOME-C4E4A596F7 ([87.69.4.28]) by mtaout24.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0NGF00IEYKENX7A0@mtaout24.012.net.il>; Thu, 11 Dec 2014 20:23:11 +0200 (IST) In-reply-to: <20141211174508.GC581@thyrsus.com> X-012-Sender: halo1@inter.net.il X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 80.179.55.180 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:179812 Archived-At: > Date: Thu, 11 Dec 2014 12:45:08 -0500 > From: "Eric S. Raymond" > Cc: emacs-devel@gnu.org > > Eli Zaretskii : > > > In other VCSes it would be difficult to even attempt this. > > > > ??? It's known as "reverse cherry-picking", and is AFAIK possible in > > Git, bzr, and hg. > > > > Or maybe I don't understand what ttn was alluding to. > > You don't, not quite. Reverse cherry pick doesn't actually do the git > equivalent of removing a delta; the history is not altered. Reverse > cherry pic only requires forward composition of a reversed patch onto > the current branch tip - a much, *much* more tractable problem. Of course! But that's the only possible way in modern VCSs to do that, and the human-level abstraction is the same. > The git equivalent of actually removing a delta would be *really hard*. I didn't (and couldn't) mean that.