From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Stephen J. Turnbull" Newsgroups: gmane.emacs.devel Subject: Re: resolving ambiguity in action stamps Date: Mon, 15 Sep 2014 00:45:36 +0900 Message-ID: <878ulm434v.fsf@uwakimon.sk.tsukuba.ac.jp> References: <87wq9841zx.fsf@uwakimon.sk.tsukuba.ac.jp> <20140913053525.GA15582@thyrsus.com> <87tx4c3t4k.fsf@uwakimon.sk.tsukuba.ac.jp> <20140913.092630.2301242291023129455.hanche@math.ntnu.no> <20140913105058.GA16776@thyrsus.com> <87r3ze4pw6.fsf@uwakimon.sk.tsukuba.ac.jp> <20140914105531.GA30576@thyrsus.com> <87egve49d9.fsf@uwakimon.sk.tsukuba.ac.jp> <20140914142117.GA935@thyrsus.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 X-Trace: ger.gmane.org 1410709574 17319 80.91.229.3 (14 Sep 2014 15:46:14 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 14 Sep 2014 15:46:14 +0000 (UTC) Cc: Harald Hanche-Olsen , emacs-devel@gnu.org To: esr@thyrsus.com Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sun Sep 14 17:46:07 2014 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XTC07-00051A-JS for ged-emacs-devel@m.gmane.org; Sun, 14 Sep 2014 17:46:07 +0200 Original-Received: from localhost ([::1]:55078 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XTC07-0008OW-1W for ged-emacs-devel@m.gmane.org; Sun, 14 Sep 2014 11:46:07 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:53545) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XTBzn-0008KW-Rr for emacs-devel@gnu.org; Sun, 14 Sep 2014 11:45:55 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XTBzg-0001nC-CN for emacs-devel@gnu.org; Sun, 14 Sep 2014 11:45:47 -0400 Original-Received: from shako.sk.tsukuba.ac.jp ([130.158.97.161]:52006) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XTBzf-0001mi-SY for emacs-devel@gnu.org; Sun, 14 Sep 2014 11:45:40 -0400 Original-Received: from uwakimon.sk.tsukuba.ac.jp (uwakimon.sk.tsukuba.ac.jp [130.158.99.156]) by shako.sk.tsukuba.ac.jp (Postfix) with ESMTP id 0A99D1C38D1; Mon, 15 Sep 2014 00:45:37 +0900 (JST) Original-Received: by uwakimon.sk.tsukuba.ac.jp (Postfix, from userid 1000) id EF3521A28C8; Mon, 15 Sep 2014 00:45:36 +0900 (JST) In-Reply-To: <20140914142117.GA935@thyrsus.com> X-Mailer: VM undefined under 21.5 (beta34) "kale" acf1c26e3019 XEmacs Lucid (x86_64-unknown-linux) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 130.158.97.161 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:174290 Archived-At: Eric S. Raymond writes: > It is still a technical fact that no git translation containing SHA1s > can be built without passing through a VCS-independent representation > of commit refs on the way. Fact!? I would use the bzr revid, and insert the revid, SHA1 pair after I commit each new revision in git on Pass 1. What am I missing? (Read your next paragraph and my reply first!) > Yeah, that'd be nice, if a functional equivalent of filter-branch > could do the job at all by itself. No chance of that: see above > about hash mixing. Of course my proposal needs a database that's writable, and must update the bzr id to git id mapping every time filter-branch makes a new commit. It's not trivial, but it's not going to be hard. Unless you think there are Emacs developers smart enough to refer to bugs that will occur in as-yet uncommitted revisions by revid? Speaking of databases: since AFAIK you're basically done creating git blobs and trees (ie, except for new commits to the public repo), I assume you are using a pre-primed object db when you run your conversion? If not, you should get a 20% speed up or so. You might be able to get a lot more speed up if you could just work with bzr log and git filter-branch. (That's a pretty crazy idea and quite possibly not at all worth the work even if possible. But let me throw it out there....) > > Actually, I disagree. It would be a really good thing if they > > are precise. Do you really want to put anybody through the > > trouble of translating randomized format cookies, which may point > > to any of several commits, again? Then revising their scripts > > every time a new variant shows up? > > It has yet to be demonstrated that this is a problem in a real use > case. And, actually, I already checked this; the Emacs history > doesn't have any version-stamp collisions in actually referenced > revisions. That's not what I'm talking about. I'm talking about 2014/09/15!esr@thyrsus.com vs. 2014-09-15/esr@thyrsus.com vs. 9/15/2014!esr vs. .... People *will* handwrite those references, precisely because they're more or less human-readable. > > Existence proof comes before characterization, please. Ie, I suppose you don't get any collisions in referenced revisions. But we know that there could be. Maybe "almost correct" is good enough for you, but I think Emacs deserves better from its VCS. Worse is not better when best already exists.