From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21913 invoked by alias); 19 May 2019 12:48:44 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 21905 invoked by uid 89); 19 May 2019 12:48:43 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-1.0 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.1 spammy=urge, href, alone, HContent-type:charset X-HELO: snark.thyrsus.com Received: from thyrsus.com (HELO snark.thyrsus.com) (71.162.243.5) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Sun, 19 May 2019 12:48:41 +0000 Received: by snark.thyrsus.com (Postfix, from userid 1000) id 4B07B4704861; Sun, 19 May 2019 08:48:40 -0400 (EDT) From: esr@thyrsus.com (Eric S. Raymond) To: gcc@gcc.gnu.org, Martin =?utf-8?Q?Li=C5=A1ka?= Subject: Tradeoffs in the quality of GCC's repository conversion MIME-version: 1.0 Content-type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Message-Id: <20190519124840.4B07B4704861@snark.thyrsus.com> Date: Sun, 19 May 2019 12:48:00 -0000 X-IsSubscribed: yes X-SW-Source: 2019-05/txt/msg00149.txt.bz2 Recent discussion of whether the GCC team can live with an absence of SVN references references in a converted repository is emblematic of a larger problem. In this and other respects, Martin Liška's a approach is a clever kluge that will produce a low-quality conversion. I won't tell you not to go this route; it's your decision, and I cannot yet absolutely rule out the possibility that even with the Go translation of reposurgeon complete it is not a practical tool at this scale. But I do urge you not to jump without thinking through the tradeoffs carefully. It's a pretty classic speed-vs-quality decision. When I get that translation done, I should be able to produce a conversion that can be demonstrated correct even near branches with confused metadata due to SVN operator errors, which is the big ugly case that ad-hoc approaches like mliska's basically cannot get right - they don't do enough global analysis to resolve the defects. It is unfortunately true that I don't know when I'll be able to do this. I think the odds that I will in fact be able to are 85%-90%, but I can't predict a completion date. The surrounding problems are genuinely hard, I'm working alone on this, and I have to spend a lot of my time on work that pays bills. Still...if you opt for a quick, inexact conversion, do it with your eyes open. There will be a price for that choice later on when you trip over the defects that a naive approach not only doesn't fix but can actually amplify. -- Eric S. Raymond "The state calls its own violence `law', but that of the individual `crime'" -- Max Stirner From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 64158 invoked by alias); 19 May 2019 15:52:46 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 64150 invoked by uid 89); 19 May 2019 15:52:46 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-3.2 required=5.0 tests=AWL,BAYES_00,SPF_PASS autolearn=ham version=3.3.1 spammy=theoretically, price, quality X-HELO: mx1.suse.de Received: from mx2.suse.de (HELO mx1.suse.de) (195.135.220.15) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Sun, 19 May 2019 15:52:45 +0000 Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 0A3FEAF2A; Sun, 19 May 2019 15:52:43 +0000 (UTC) Subject: Re: Tradeoffs in the quality of GCC's repository conversion To: "Eric S. Raymond" , gcc@gcc.gnu.org References: <20190519124840.4B07B4704861@snark.thyrsus.com> From: =?UTF-8?Q?Martin_Li=c5=a1ka?= Message-ID: Date: Sun, 19 May 2019 15:52:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190519124840.4B07B4704861@snark.thyrsus.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-IsSubscribed: yes X-SW-Source: 2019-05/txt/msg00150.txt.bz2 On 5/19/19 2:48 PM, Eric S. Raymond wrote: > Recent discussion of whether the GCC team can live with an absence > of SVN references references in a converted repository is emblematic > of a larger problem. Hi. First, can you please reply to the email conversation that's happening on gcc-patches mailing list (Subject: Add scripts to convert GCC repo from SVN to Git). > > In this and other respects, Martin Liška's a approach is a clever > kluge that will produce a low-quality conversion. Can you please be more precise? Note the initiative is done by Maxim Kuvyrkov and he's proposing to use git-svn. Is it what you mean? I only prepared the author map from your repository and it's not yet decided whether to apply it or not. > I won't tell you > not to go this route; it's your decision, and I cannot yet absolutely > rule out the possibility that even with the Go translation of > reposurgeon complete it is not a practical tool at this scale. > > But I do urge you not to jump without thinking through the tradeoffs > carefully. It's a pretty classic speed-vs-quality decision. > > When I get that translation done, I should be able to produce a > conversion that can be demonstrated correct even near branches with > confused metadata due to SVN operator errors, which is the big ugly > case that ad-hoc approaches like mliska's basically cannot get right - > they don't do enough global analysis to resolve the defects. As it was mentioned multiple times. Most of the contributors are pretty happy with current git mirror and can theoretically start with that as a git repository that will replace the SVN. Martin > > It is unfortunately true that I don't know when I'll be able to do > this. I think the odds that I will in fact be able to are 85%-90%, > but I can't predict a completion date. The surrounding problems are > genuinely hard, I'm working alone on this, and I have to spend a lot of > my time on work that pays bills.> > Still...if you opt for a quick, inexact conversion, do it with your > eyes open. There will be a price for that choice later on when you > trip over the defects that a naive approach not only doesn't fix but > can actually amplify. > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 57118 invoked by alias); 19 May 2019 17:37:44 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 57109 invoked by uid 89); 19 May 2019 17:37:44 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-1.0 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.1 spammy=announcement, HX-Languages-Length:610, H*f:sk:fea1c82, H*i:sk:fea1c82 X-HELO: snark.thyrsus.com Received: from thyrsus.com (HELO snark.thyrsus.com) (71.162.243.5) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Sun, 19 May 2019 17:37:42 +0000 Received: by snark.thyrsus.com (Postfix, from userid 1000) id 6289C4703049; Sun, 19 May 2019 13:37:41 -0400 (EDT) Date: Sun, 19 May 2019 17:37:00 -0000 From: "Eric S. Raymond" To: Martin =?utf-8?B?TGnFoWth?= Cc: gcc@gcc.gnu.org Subject: Re: Tradeoffs in the quality of GCC's repository conversion Message-ID: <20190519173741.GA86680@thyrsus.com> Reply-To: esr@thyrsus.com References: <20190519124840.4B07B4704861@snark.thyrsus.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-IsSubscribed: yes X-SW-Source: 2019-05/txt/msg00151.txt.bz2 Martin Liška : > > In this and other respects, Martin Liška's a approach is a clever > > kluge that will produce a low-quality conversion. > > Can you please be more precise? Note the initiative is done by Maxim Kuvyrkov > and he's proposing to use git-svn. Is it what you mean? Yes, sorry, I misunderstood a reference. On the subject of git-svn, here is a public service announcement I wrote in 2015: http://esr.ibiblio.org/?p=6778 I'll subscribe to gcc-patches now. -- Eric S. Raymond