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=-5.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD shortcircuit=no autolearn=ham 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 A3DC9203E1 for ; Wed, 27 Jul 2016 16:53:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757097AbcG0QxR (ORCPT ); Wed, 27 Jul 2016 12:53:17 -0400 Received: from mail-io0-f180.google.com ([209.85.223.180]:35438 "EHLO mail-io0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752446AbcG0QxQ (ORCPT ); Wed, 27 Jul 2016 12:53:16 -0400 Received: by mail-io0-f180.google.com with SMTP id m101so75730582ioi.2 for ; Wed, 27 Jul 2016 09:53:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=jbMvY6TL4ap+RFHjUKAYpiTLf6NncVdPi8IporYM4+4=; b=Ce0I7cVGDe73lret6+LBSV5msAo1w2BB/c/9xLORZXkcN9Bp5rl96ZuVWF+9E7+3tL TQkt7q93Ux2mTUB744bOeY6FAkXspZcDP93AjShnJZ633P/iljvUfybQuMKsWce433xu RpxVHDr7NlY9CyMpc3hjP2EtUYUtR8U0bcRLbUQhBHxNq0QouzeoI6ePMbWPe7gUPxgt CjX/IhWhxnG2h0dOoFqKcy2hLnioErTvuRozSGvRhipEy+daK7VKdIXujSOMcm8BIx7p r3Mwg0N5KNKoKVhYSLCBNaIJ+ySL+Gz66WK5+CHZeyIdz10cQjlJY7QJSBElL/EMDVcp bP+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=jbMvY6TL4ap+RFHjUKAYpiTLf6NncVdPi8IporYM4+4=; b=gKJ8mVU4E74beu+nnkE1zmK6U8xX4rXtiYaNCO7ha3HkS4517+C/vT1JyMyUrqni7Q lXu7Dwy3NBoqfae5oY5PLpsfVPcQpXR2L5Li75sYPPXBkDDUscdMCUN9af4wELI5UUH0 7/njf1Sl054QwB+Ktu8RiUxS3yfeBpe33LZad/rAaUK+aW1aGwuS9ojunxyhIOj6Y6H6 AMMb6RcOZOZfknXIG0+eR/Zu2I127Ny98iksInOjK7RtBkQqumFBmceSziHbviafgV1J Tm8nZYd8gduRM159sm4fZIPblsVi3mAMfluK3qYHgbZq4EmP0leGJF68IfnopA31BPFJ a3Jg== X-Gm-Message-State: AEkoouvUz+/bAEQZeaDM+rImzIqG/5pOD4GyrkOV1anVnG9PldZz69RWkVuA+wGbPIhlxjXTzxhHARDkECqYFJi4 X-Received: by 10.107.144.10 with SMTP id s10mr32255989iod.165.1469638394566; Wed, 27 Jul 2016 09:53:14 -0700 (PDT) MIME-Version: 1.0 Received: by 10.107.128.66 with HTTP; Wed, 27 Jul 2016 09:53:13 -0700 (PDT) In-Reply-To: <5798C744.5080308@gmail.com> References: <20160720172419.25473-1-pclouds@gmail.com> <20160720172419.25473-4-pclouds@gmail.com> <5798C744.5080308@gmail.com> From: Stefan Beller Date: Wed, 27 Jul 2016 09:53:13 -0700 Message-ID: Subject: Re: [PATCH v4 3/4] submodule: support running in multiple worktree setup To: =?UTF-8?Q?Jakub_Nar=C4=99bski?= Cc: Duy Nguyen , Jonathan Nieder , "git@vger.kernel.org" , Max Kirillov , Junio C Hamano , Michael J Gruber , Jens Lehmann , Lars Schneider , Michael Haggerty Content-Type: text/plain; charset=UTF-8 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Jakub wrote: > I think the problem with `--reference` is that it does not > setup backreferences to prevent gc removing borrowed objects; > which is a hard problem to solve, except for limited cases... > like git-worktree. Right. And instead of solving the reference problem, I'd rather solve the worktree problem as I think it yields more? > >> So I think the current workflow for submodules >> may need some redesign anyway as the submodule >> commands were designed with a strict "one working >> tree only" assumption. >> >> Submodule URLs are stored in 3 places: >> A) In the .gitmodules file of the superproject >> B) In the option submodule..URL in the superproject >> C) In the remote.origin.URL in the submodule >> >> A) is a recommendation from the superproject to make life >> of downstream easier to find and setup the whole thing. >> You can ignore that if you want, though generally a caring >> upstream provides good URLs here. > > Also, this URL might have change if the repository moves > to other server; even when checking out ancient version > we usually want to use current URL, not the one in currently > checked-out .gitmodules file. Right. > >> C) is where we actually fetch from (and hope it has all >> the sha1s that are recorded as gitlinks in the superproject) > > Is it? Or is it only the case if you do `git fetch` or > equivalent from within inside of submodule? You can fetch > updates using `git submodule ...` from supermodule, isn't it? > But I might be wrong here. If you call `submodule update` in the superproject it actually just does a `(cd $submodule && git fetch)`. And in the submodule we have a .git file pointing to the superprojects ".git/modules//" which is a full blown git dir, i.e. it has its own config, HEAD etc. > > Also: if .git file is gitfile link, do submodule even has > it's own configuration file? Yes they do. > >> >> B) seems like a hack to enable the workflow as below: > > It has overloaded meaning, being used both for current URL > of submodule as seen in supermodule, AND that submodule > is checked out / needs to be checked out in the worktree > of a supermodule. There might be the case when you check > out (in given worktree) a version of a supermodule that > do not include submodule at all, but you want to know that > when going back, this submodule is to be checked out (or not). I am currently working on solving that with a patch series, that allows 2 settings. The URL will be used only to overwrite the URL from the .gitmodules file and another setting will be used to determine if we want to checkout the submodule. > > The second information needs to be per-worktree. How to > solve it, be it per-worktree configuration (not shared), > or a special configuration variable, or worktree having > unshared copy of configuration -- this what is discussed. > >> Current workflow for handling submodule URLs: >> 1) Clone the superproject >> 2) Run git submodule init on desired submodules > > Or 1-2) clone the superproject recursively, with all its > submodules. Only if the URLs are setup properly. > >> 3) Inspect .git/config to see if any submodule URL needs adaption > > Which is usually not needed. Yeah, I should have added the assertion that the .gitmodules may be out of date or such for this workflow to make sense. Usually just go with recursive clone. >> >> This long lived stuff probably doesn't make sense for the a single >> repository, but in combination with submodules (which is another way >> to approach the "sparse/narrow" desire of a large project), I think >> that makes sense, because the "continuous integration" shares a lot >> of submodules with my "regular everyday hacking" or the "I need to >> test my colleague work now" worktree. > > One thing that git-worktree would be very useful, if it could work > with submodules: you could use separate worktrees to easily test > if the supermodule works with and without its submodules present. Oh! Yeah that makes sense! > > [...] >> If you switch a branch (or to any sha1), the submodule currently stays >> "as-is" and may be updated using "submodule update", which goes through >> the list of existing (checked out) submodules and checks them out to the >> sha1 pointed to by the superprojects gitlink. > > Which might be simply a problem that submodule UI is not mature enough. > I would like to see automatic switch of submodule contents, if > configured so. Me too. Once upon a time Jens pushed for that with a series found at: https://github.com/jlehmann/git-submod-enhancements/tree/git-checkout-recurse-submodules