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=-2.7 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,RCVD_IN_SORBS_SPAM, RP_MATCHES_RCVD,T_DKIM_INVALID 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 B5AF1207FF for ; Thu, 4 May 2017 04:29:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752588AbdEDE3t (ORCPT ); Thu, 4 May 2017 00:29:49 -0400 Received: from mail-pf0-f196.google.com ([209.85.192.196]:35142 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752098AbdEDE3s (ORCPT ); Thu, 4 May 2017 00:29:48 -0400 Received: by mail-pf0-f196.google.com with SMTP id o68so480264pfj.2 for ; Wed, 03 May 2017 21:29:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:references:date:in-reply-to:message-id :user-agent:mime-version; bh=+LOzONKuK+b2OjAxVfPD9CKeRLv4uzJQjLZOAUVXljo=; b=lrmfIe90eqFgomDf/DE1Z3EnehZFmuGjzBJ7iAUMj0ds98OzhrbIM0ZTvyRAS+jn/9 SdZWhRA3S4l5qkl3dFlFuYdVA8FtzVDTqu4MGKtkxDaf7wUOhbDH1xWwIRepqyeTU3k1 iK6VUIWvASMYATlixVLfqN2abQ3q0p14HiD7ddVG6XMIOFoJDjyqmZGUbxTqdfGYNQC7 EhrfayE5jWsraKzP6jK/QAY0cli2+6aYUIHdok8OtG/x+KX3Aw8nZ2B0CyvAjzeXEMpA Np/21IinJQk2M1PDVKZ3jEhxoCJjTcAymZOU5rU/9ZeffZqgzn+k5yaImMBPg37MiwVI yj5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:references:date :in-reply-to:message-id:user-agent:mime-version; bh=+LOzONKuK+b2OjAxVfPD9CKeRLv4uzJQjLZOAUVXljo=; b=HxeISTAvWMNhROOjpCRr0ujMh3infl5JFsRSzSJoezHhX9nXqLAOYilXu0NbyVB3ei CUxem9dlKaZdbfGmH9ieEBtN2a1XHPNKG82MWr+Ad2NKLU2jzpfWNk3d7qmOC1HmHaMP kOO46jB9RyvfYVc1W6UiJEpF6UZxKb2WGqSHHAp378TbUYW2bmwF3rzT8YHtHzfvxOwT tjbT6XEzgRSPNqZXC0gMBJjVjMfs/KrCuEHVAbRiVqZe43iYIDfDotfPIJKvHkMpxoo5 5zeCx9/dzuwIf6JRlpGpdP7I5TXy1oBGwdEBulw2lUkd+HrvCo887nePGUMQFGQH1qbw 2wMA== X-Gm-Message-State: AN3rC/7bMFtJ6qkT9RRQHMeaWlu7lCntguJdDSkGB59edcrNYoA+CVFj Ys9eCXkWDlw08Q== X-Received: by 10.99.167.3 with SMTP id d3mr42490168pgf.70.1493872187550; Wed, 03 May 2017 21:29:47 -0700 (PDT) Received: from localhost ([2620:0:1000:8622:21be:aa3e:8063:4b3]) by smtp.gmail.com with ESMTPSA id r13sm1120275pgn.16.2017.05.03.21.29.46 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Wed, 03 May 2017 21:29:46 -0700 (PDT) From: Junio C Hamano To: Jonathan Tan Cc: =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason , Git mailing list , Mark Thomas , Jeff Hostetler , Kevin David Subject: Re: Proposal for missing blob support in Git repos References: <20170426221346.25337-1-jonathantanmy@google.com> <193d1d84-2386-c4c8-81ef-0042f0d8bb02@google.com> Date: Wed, 03 May 2017 21:29:46 -0700 In-Reply-To: (Jonathan Tan's message of "Tue, 2 May 2017 14:45:06 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.91 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Jonathan Tan writes: > I see the semantics as "don't write what you already have", where > "have" means what you have in local storage, but if you extend "have" > to what upstream has, then yes, you're right that this changes > (ignoring shallow clones). > > This does remove a resistance that we have against hash collision (in > that normally we would have the correct object for a given hash and > can resist other servers trying to introduce a wrong object, but now > that is no longer the case), but I think it's better than consulting > the hook whenever you want to write anything (which is also a change > in semantics in that you're consulting an external source whenever > you're writing an object, besides the performance implications). As long as the above pros-and-cons analysis is understood and we are striking a balance between performance and strictness with such an understanding of the implications, I am perfectly fine with the proposal. That is why my comment has never been "I think that is wrong" but consistently was "I wonder if that is a good thing." Thanks.