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=-3.4 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, T_DKIM_INVALID 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 B48DA1F404 for ; Mon, 16 Apr 2018 22:34:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751210AbeDPWet (ORCPT ); Mon, 16 Apr 2018 18:34:49 -0400 Received: from mail-wr0-f174.google.com ([209.85.128.174]:42417 "EHLO mail-wr0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750917AbeDPWer (ORCPT ); Mon, 16 Apr 2018 18:34:47 -0400 Received: by mail-wr0-f174.google.com with SMTP id s18so30214719wrg.9 for ; Mon, 16 Apr 2018 15:34:47 -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=qmj7yMu8LfsMh69FpKh64QmkMNhHCTzAjwSjsFL0ges=; b=RfgzJrQmJzCr8TABRKJcf1ZPXxfofyPup6gbg+90wCMyjOVEacGTisQFf7RxQ+7EjJ dBdMJ+cBctghOIXJrUsZk3hKSLF2o8u1BW4EErcRfEnlnv6X1bPsBP/QkVKpy2/Cj3zp QBo7K9KcZiyI58m0K/W3Q1gt0e144zVP8I004pF2tPGyAJ/TAHUgtfZxERXLmgR4XitK EK7lAA3HkrB+UtVj6xQSrGl8coSXUR/ZERb6aqctt8IORKG+/SErEifeEQeOxn9mugKm aOV52gMJkhAzkt8TKrtQtk+KP7OFzcEGwah7o1caanoIEzidkMSOVfJjq27Y6plNKbXa rVHw== 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=qmj7yMu8LfsMh69FpKh64QmkMNhHCTzAjwSjsFL0ges=; b=CsQ2XpspNSGudzRvUD33kI4GL+ailzW0LKB6rtEGkx2d5AQlvzuRN2vl4BoYHNJmyJ 6OtyjR46UgCULx+M+aV3oDBTnJ+v6AlYSm5z92ZI66OmDgcfQ3Y1w5tUOXDiF70yHmI/ ulD66efqBOJOgg9pS6ywYEDJL/sfWgpZ/6SNmEEmVrhTXwHDGQ8Bzk7D6L3hj+iE6QH2 kM7OppY/u9M+8oelCZGFt5j5GJYEkCQwiaG7sTFbllZXGD5vtpunJSdMK9iCLIw+geor 3yAQIh6k3WS5928I+Jx2XCfz1LQF2CHSRhMxnz0szh9g5AKMDnunVGydcjHm0cBqd4RB k/gQ== X-Gm-Message-State: ALQs6tD2oPsUNZVolwLS5i0H01wfKbnTRF3mtSljffwMe+OKpk/8dLMz j5keB9sPlI3ucpf1qJ21LM4= X-Google-Smtp-Source: AIpwx49NI7KLsjHnQ1uhD7xyTIavER2hGaw46TF3qElUWzbQPH9g35egfemeXOHEslVO2ClNJLnUzA== X-Received: by 10.28.107.5 with SMTP id g5mr49639wmc.133.1523918086335; Mon, 16 Apr 2018 15:34:46 -0700 (PDT) Received: from localhost (112.68.155.104.bc.googleusercontent.com. [104.155.68.112]) by smtp.gmail.com with ESMTPSA id 4sm4703959wrz.58.2018.04.16.15.34.45 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 16 Apr 2018 15:34:45 -0700 (PDT) From: Junio C Hamano To: Jacob Keller Cc: Lars Schneider , Linus Torvalds , Elijah Newren , Git Mailing List , mgorny@gentoo.org, Peter Backes , winserver.support@winserver.com, "Theodore Ts'o" Subject: Re: Optimizing writes to unchanged files during merges? References: Date: Tue, 17 Apr 2018 07:34:45 +0900 In-Reply-To: (Jacob Keller's message of "Mon, 16 Apr 2018 10:45:29 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2.50 (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 Jacob Keller writes: > On Mon, Apr 16, 2018 at 10:43 AM, Jacob Keller wrote: > ... > I think a better solution for your problem would be to extend the > build system you're using to avoid rebuilding when the contents > haven't changed since last build (possibly by using hashes?). At the > very least, I would not want this to be default, as it could possibly > result in *no* build when there should be one, which is far more > confusing to debug. Yup. Even though I take many optional features that I do not see need to support on the core side and I do not plan to use personally, as long as the implementation is cleanly separated to make it clear that those who do not use them won't negatively affected, I would not want to have this in a system I maintain and get blamed by those who get burned by it. Something like ccache, not a version control system, is meant to serve this audience.