From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-2.6 required=3.0 tests=AWL,BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_HI,T_RP_MATCHES_RCVD shortcircuit=no autolearn=no autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 928E71F404 for ; Sun, 11 Feb 2018 00:10:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753027AbeBKAKi (ORCPT ); Sat, 10 Feb 2018 19:10:38 -0500 Received: from mout.gmx.net ([212.227.15.15]:41531 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753011AbeBKAKf (ORCPT ); Sat, 10 Feb 2018 19:10:35 -0500 Received: from MININT-TB4PCE7.southpacific.corp.microsoft.com ([37.201.195.115]) by mail.gmx.com (mrgmx003 [212.227.17.190]) with ESMTPSA (Nemesis) id 0LqALY-1fFLCm2xVo-00dk1A; Sun, 11 Feb 2018 01:10:28 +0100 Date: Sun, 11 Feb 2018 01:10:27 +0100 (STD) From: Johannes Schindelin X-X-Sender: virtualbox@MININT-6BKU6QN.europe.corp.microsoft.com To: git@vger.kernel.org cc: Junio C Hamano , Jacob Keller , Stefan Beller , Philip Oakley , Eric Sunshine , Phillip Wood Subject: [PATCH v3 08/12] rebase: introduce the --recreate-merges option In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21.1 (DEB 209 2017-03-23) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Provags-ID: V03:K0:1IL3o3o/S1XgE9QHZtw49lVvQyqOOtu74AzhqJPcjBiPrgZXAI+ fKNcz/IDSkpssKkIOfqFvtK+Sc3BIYq6IFB0NwmcMqNFwBHuHY2jEo7g0SqjYNSBv5O23nb 6px9frWcaIJGN1yEvsykHZ6VTZI97PEzg1dBaAGMfub/pLZF3DCXnSYxbmERAwVuyhkXUMK bdLs2Tr0YswDbkvq71RUw== X-UI-Out-Filterresults: notjunk:1;V01:K0:pb5bl9b/i40=:GEyP4gmnIB5dUTPVVepqJ+ ucR4Yuvr/iWYTKXMm8O8aKSjD9bW1TIjcr8vwdtOzKpE7cqQySe2VlaDT69Z4leAti5tfmnVT SACWwkaKynp5dvaicSqh6txzEvGU8mTpUrlbMhQa0KW/B4gjRxLg7eRrd1LDaTf0lqbcDNyB3 uFRPGY2RAslvKnNA5SrxKIiHRy35fE5mpeZyRdBRj3hDWtHKd7jHtVJXfs4gzquH/09OaYphC x2qKY0FEVdKbZuLuckrHdZpK+vloivvQzCHG+fCY3qdhiXyNYYUwVcAf3il/HJDw/ilbVWYsE I4bG+VVeMDR3s1yoeE9OhzS5g8SB477M0w90mQxLi8ob9uP6cYjCJQ2yN2k2YVSG8Al/iKqHM Q8tOTWjP4Yqf96rZv1o++qFAnFpCsxcl4TG2yXrFEwFh7WxFf93XRlx0TOstIv4sfhsWMM/Tr KOnjD5/+8YfLRU7ydGXUVpEybedOmxnafi1g6gBdPbTdepZW6YQgN+wQLEFjhE1kPmDVXoeGu s3tf2RsjE9DPK1SRT9KqosOTxIXxrefPZs9njiE1yVQmn3IblmUOQokUAIbEPAPhdV55opeHH k3NZghegdioiSgwfGpek/9ohwTj0ew2EOE05SbuUqGgrHGqMOAqizdHfAu/3rymfyr7d+X3GP cGRoW597Fyr9mGIykX/Au5y1qylap9at0Wx4SiHVPpwgI/MGzJRVQ1ogjfzYv4R7KzIGg7CKy bBcUodiqF4XNmcH7ILfeEeFjrMAjMHMrryFfBOnnDoBhw/GmwV1L6onmz8gqxyz4L+I98JcfW y4NlzYJcBx7IBI33jaE139tu+uYcYseLm8siSqZPd59bsWmj1U= Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Once upon a time, this here developer thought: wouldn't it be nice if, say, Git for Windows' patches on top of core Git could be represented as a thicket of branches, and be rebased on top of core Git in order to maintain a cherry-pick'able set of patch series? The original attempt to answer this was: git rebase --preserve-merges. However, that experiment was never intended as an interactive option, and it only piggy-backed on git rebase --interactive because that command's implementation looked already very, very familiar: it was designed by the same person who designed --preserve-merges: yours truly. Some time later, some other developer (I am looking at you, Andreas! ;-)) decided that it would be a good idea to allow --preserve-merges to be combined with --interactive (with caveats!) and the Git maintainer (well, the interim Git maintainer during Junio's absence, that is) agreed, and that is when the glamor of the --preserve-merges design started to fall apart rather quickly and unglamorously. The reason? In --preserve-merges mode, the parents of a merge commit (or for that matter, of *any* commit) were not stated explicitly, but were *implied* by the commit name passed to the `pick` command. This made it impossible, for example, to reorder commits. Not to mention to flatten the branch topology or, deity forbid, to split topic branches into two. Alas, these shortcomings also prevented that mode (whose original purpose was to serve Git for Windows' needs, with the additional hope that it may be useful to others, too) from serving Git for Windows' needs. Five years later, when it became really untenable to have one unwieldy, big hodge-podge patch series of partly related, partly unrelated patches in Git for Windows that was rebased onto core Git's tags from time to time (earning the undeserved wrath of the developer of the ill-fated git-remote-hg series that first obsoleted Git for Windows' competing approach, only to be abandoned without maintainer later) was really untenable, the "Git garden shears" were born [*1*/*2*]: a script, piggy-backing on top of the interactive rebase, that would first determine the branch topology of the patches to be rebased, create a pseudo todo list for further editing, transform the result into a real todo list (making heavy use of the `exec` command to "implement" the missing todo list commands) and finally recreate the patch series on top of the new base commit. That was in 2013. And it took about three weeks to come up with the design and implement it as an out-of-tree script. Needless to say, the implementation needed quite a few years to stabilize, all the while the design itself proved itself sound. With this patch, the goodness of the Git garden shears comes to `git rebase -i` itself. Passing the `--recreate-merges` option will generate a todo list that can be understood readily, and where it is obvious how to reorder commits. New branches can be introduced by inserting `label` commands and calling `merge