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=-4.7 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 CB3FA1F859 for ; Wed, 31 Aug 2016 16:42:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161093AbcHaQmn (ORCPT ); Wed, 31 Aug 2016 12:42:43 -0400 Received: from pb-smtp2.pobox.com ([64.147.108.71]:64184 "EHLO sasl.smtp.pobox.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1161082AbcHaQmj (ORCPT ); Wed, 31 Aug 2016 12:42:39 -0400 Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by pb-smtp2.pobox.com (Postfix) with ESMTP id AD99338ABC; Wed, 31 Aug 2016 12:42:37 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=gGaXIjdXMlymNsjbCD3AJnD6Pjc=; b=EhqqMp OphwRi2Y1xWrEju0mfSCG4Mh3dkT7w4bCC6hdgE1G4QFTmotafGIS8+saztUgwcs NPXeln05BDnUfe17YXGkJhwBKFy6x/3BlSPahew0XcQFVBiftkokHM4xZd6nj62e dDYF5D2XgzjA9//li01wGocQw29N/XNtOKVio= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; q=dns; s=sasl; b=cmqfmdZ6tyFi/iYkiEtDh4qiTfa1KZpp aIORfcGsThh5gA5UWYC73nQgKuOvJuhLPj25zG/hmpCfDqIA02JguEcoX2TwfLR0 kDzDegmLkXlCzojFtAaLLQY7nWKWxauag7uuNnpt/YjPhpx5t4M7KbK0PF+ZjJRm 4KoLJq0ax8s= Received: from pb-smtp2.nyi.icgroup.com (unknown [127.0.0.1]) by pb-smtp2.pobox.com (Postfix) with ESMTP id A676B38ABB; Wed, 31 Aug 2016 12:42:37 -0400 (EDT) Received: from pobox.com (unknown [104.132.0.95]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by pb-smtp2.pobox.com (Postfix) with ESMTPSA id 2B5EE38AB7; Wed, 31 Aug 2016 12:42:37 -0400 (EDT) From: Junio C Hamano To: Uma Srinivasan Cc: Jacob Keller , Git Mailing List , Jens Lehmann , Heiko Voigt , Stefan Beller Subject: Re: git submodules implementation question References: Date: Wed, 31 Aug 2016 09:42:35 -0700 In-Reply-To: (Uma Srinivasan's message of "Tue, 30 Aug 2016 19:54:12 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Pobox-Relay-ID: EC9F560E-6F99-11E6-B797-51057B1B28F4-77302942!pb-smtp2.pobox.com Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Uma Srinivasan writes: >> I might suggest to update prepare_submodule_repo_env() so that the >> spawned process will *NOT* have to guess where the working tree and >> repository by exporting GIT_DIR (set to "git_dir" we discover above) >> and GIT_WORK_TREE (set to "." as cp.dir is set to the path to the >> working tree of the submodule). That would stop the "git status" to >> guess (and fooled by a corrupted dir/.git that is not a git >> repository). > > Here's where I am struggling with my lack of knowledge of git > internals and the implementation particularly in the context of how > environment variables are passed from the parent to the child process. Ah, I was primarily addressing Jacob in the latter part of my message, as he's looked at similar things in his recent topic. > Are you suggesting that we set up the child process environment array > (the "out" argument) in prepare_submodule_repo_env() to include > GIT_DIR_ENVIRONMENT and GIT_WORK_TREE_ENVIRONMENT in addition to > CONFIG_DATA_ENVIRONMENT that is there now? I was wondering if we should unconditionally stuff GIT_DIR= in the cp.env_array passed to the function prepare_submodule_repo_env(). As cp.dir will be set to the submodule's working tree, there is no need to set GIT_WORK_TREE and export it, I think, although it would not hurt. After all, we _are_ going into a separate and different project's repository (that is what a submodule is), and we _know_ where its repository data (i.e. GIT_DIR) and the location of its working tree (i.e. GIT_WORK_TREE). There is no reason for the process that will work in the submodule to go through the usual "do we have .git in our $cwd that is a repository? if not how about the parent directory of $cwd? go up until we find one and that directory is the top of the working tree" discovery. More importantly, this matters when your GIT_DIR for the submodule is somehow corrupt. The discovery process would say "there is .git in $cwd but that is not a repository" and continue upwards, which likely would find the repository for the top-level superproject, which definitely is _not_ want you want to happen. And one way to avoid it is to tell the setup.c code that it should not do the discovery by being explicit.