From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael J Gruber Subject: Re: Git range merge (cherry-pick a range) Date: Thu, 16 Jul 2009 13:36:06 +0200 Message-ID: <4A5F10A6.80003@drmicha.warpmail.net> References: <24512201.post@talk.nabble.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: git@vger.kernel.org To: bshOriginal X-From: git-owner@vger.kernel.org Thu Jul 16 13:36:34 2009 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1MRPGL-0006Rd-Er for gcvg-git-2@gmane.org; Thu, 16 Jul 2009 13:36:33 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755100AbZGPLgZ (ORCPT ); Thu, 16 Jul 2009 07:36:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754997AbZGPLgZ (ORCPT ); Thu, 16 Jul 2009 07:36:25 -0400 Received: from out1.smtp.messagingengine.com ([66.111.4.25]:35446 "EHLO out1.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752242AbZGPLgY (ORCPT ); Thu, 16 Jul 2009 07:36:24 -0400 Received: from compute1.internal (compute1.internal [10.202.2.41]) by out1.messagingengine.com (Postfix) with ESMTP id E09BA3BB0D2; Thu, 16 Jul 2009 07:36:23 -0400 (EDT) Received: from heartbeat2.messagingengine.com ([10.202.2.161]) by compute1.internal (MEProxy); Thu, 16 Jul 2009 07:36:23 -0400 X-Sasl-enc: M2pCNF59IR9DuinVYE93WRiYUOeMAx9gCdSIHRx//lVf 1247744183 Received: from localhost.localdomain (heawood.math.tu-clausthal.de [139.174.44.4]) by mail.messagingengine.com (Postfix) with ESMTPSA id 2AA0F822A; Thu, 16 Jul 2009 07:36:23 -0400 (EDT) User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.1pre) Gecko/20090712 Lightning/1.0pre Shredder/3.0b3pre In-Reply-To: <24512201.post@talk.nabble.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: bshOriginal venit, vidit, dixit 16.07.2009 10:11: > > Playing around with GIT, we encountered the following strange situation for > which we would > like to have an answer: > > Scenario > ======== > > We want to merge the range B to D from branch B1 to master > > Master: o- > \ > Branch B1: A-B-C-D-E > Did you use a monospaced font when composing this e-mail? All graphs come out disconnect/distorted when reading your e-mail with a monospaced font. I assume that above, a is the first additional commit of B1 which branches off o. > > Commit B: > --------- > FluidSolver::FluidSolver(int argc, char* argv[]) { > init(argc, argv); > // test edit 1: a + b > } > > Commit C: > -------- > FluidSolver::FluidSolver(int argc, char* argv[]) { > init(argc, argv); > // test edit 1: a + b > // test edit 2: a - b > } > > Commit D: > -------- > FluidSolver::FluidSolver(int argc, char* argv[]) { > init(argc, argv); > // test edit 1: a + b > // test edit 2: a - b > // test edit 3: a * b > } > > Commit E: > -------- > FluidSolver::FluidSolver(int argc, char* argv[]) { > init(argc, argv); > // test edit 1: a + b > // test edit 2: a - b > // test edit 3: a * b > // test edit 4: a / b > } > > > Range merge (the GIT way): > ========================= > > 1) Switch to Branch B1 > > 2) Create a temporary branch which does not contain anything beyond commit D > > $ git checkout -b volatileBranch D > > Master: o- > \ > Branch B1: A-B-C-D-E > \ > Branch volatileBranch: (A)-(B)-(C)-(D) > > 3) Rebase volatile branch to master from commit (B) to master's HEAD > git rebase --onto master (A) > > > Branch volatileBranch: (B)-(C)-(D) > / > Master: o- > \ > Branch B1: A-B-C-D-E > > > Rebasing output: > ---------------- > > First, rewinding head to replay your work on top of it... > Applying: test edit 2: a - b > error: patch failed: fluidsolver.cpp:28 > error: fluidsolver.cpp: patch does not apply > Using index info to reconstruct a base tree... > Falling back to patching base and 3-way merge... > Auto-merging fluidsolver.cpp > CONFLICT (content): Merge conflict in fluidsolver.cpp > Failed to merge in the changes. > Patch failed at 0001 test edit 2: a - b > > > When you have resolved this problem run "git rebase --continue". > If you would prefer to skip this patch, instead run "git rebase --skip". > To restore the original branch and stop rebasing run "git rebase --abort". > > > Conflicts: > ---------- > FluidSolver::FluidSolver(int argc, char* argv[]) { > init(argc, argv); > <<<<<<< HEAD:fluidsolver.cpp > ======= > // test edit 1: a + b > // test edit 2: a - b >>>>>>>> test edit 2: a - b:fluidsolver.cpp > } > > > After manually resolving the conflict and continuing the rebasing > with git rebase --continue, we are finally finished. > > Since we only had updates in branch 1, it is astonishing that we get a > conflict at all. > Same situation works like a charme in subversion. Ahem, how could /anything/ work like a charm in subversion? (I've been using it myself.) Seriously, if, in subversion, you merge -rA:D onto master then subversion only computes the diff between A and D and applies it to master. You an do this in git as well, of course, but that's not a merge and does not preserve individual commit messages. > We would be happy to get an explanation for this merge bahaviour, since > many edits in large projects could as a matter of principle result a lot of > merge conflicts > which all have to be treated manually. > > We believe that GIT's interface for range merges needs to get more user > friendly. > Since steps 1) - 3) use already developed components of GIT, there should be > a layer above 'em > which performs a range merge by internally calling 1) - 3). > > Example: git cherry-pick $from_branch@startCommitHash > $to_branch@endCommitHash > If I read you graphs correctly you could just as well fast-forward master to D (using reset or merge) and then "rebase -i" in order to remove A. Alternatively, you can use "git format-patch --stdout revrange | git am". Michael