From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Chacon Subject: Re: GSoC 2010 Date: Fri, 12 Feb 2010 11:47:34 -0800 Message-ID: References: <20100212091635.GA22942@glandium.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Daniel Barkalow , Johannes Schindelin , Mike Hommey , Eric Wong , Jeff King , "Shawn O. Pearce" , Git List To: Sverre Rabbelier X-From: git-owner@vger.kernel.org Fri Feb 12 20:47:44 2010 Return-path: Envelope-to: gcvg-git-2@lo.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Ng1UM-0001dz-Dq for gcvg-git-2@lo.gmane.org; Fri, 12 Feb 2010 20:47:42 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757134Ab0BLTrh (ORCPT ); Fri, 12 Feb 2010 14:47:37 -0500 Received: from ey-out-2122.google.com ([74.125.78.24]:52642 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755973Ab0BLTrg (ORCPT ); Fri, 12 Feb 2010 14:47:36 -0500 Received: by ey-out-2122.google.com with SMTP id 9so169755eyd.5 for ; Fri, 12 Feb 2010 11:47:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type; bh=cRJqSqrn1x1tV6Zb5qr6UVPXSch23Qqh7HblORlZSI0=; b=GkzZBgBNa3Vn7YiDxpTDYTfCCOZedS3gF2tTFWaFB7aRRJugs0DXQ1FjbdLzexYr2V IvSk5y26AxdydKJWrUI/DG4jlyjoJHWhEM+yoa7Ni01ipfVij/SN4EGut43uYeBD7ajN 0MsJDfQp7OJ7rY0FK6/nBzB5cjt1uMbdhU8tA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=aCf919Jc67DJYNZw9m8wkR4TFi4JMU77wgWudNBltCDUr5yT1+02r+4b5twUc98BsP Txsrkj7K3Hr/wA3jl5lhSDIF6JYFiHIUEgANxxxpJtB3VQFCcZu+M1EjKOOCRU7Pnu1D E/gCJSQC4S0/nWjdKTHxuOpgwvpID6aAeyJoE= Received: by 10.216.89.82 with SMTP id b60mr1079996wef.170.1266004054827; Fri, 12 Feb 2010 11:47:34 -0800 (PST) In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Hey, On Fri, Feb 12, 2010 at 11:30 AM, Sverre Rabbelier wrote: > Heya, > > On Fri, Feb 12, 2010 at 20:16, Daniel Barkalow wrote: >> I think that 'export' will always have this effect, because the >> export/reimport roundtrip is practically never going to be exact with a >> remote system that isn't actually git (and the state that you see the >> remote as having after a successful push should match what you see if you >> were to clone again). > > Not so, currently round-trips to Mercurial using hg-git result in > identical commits. In most cases, this is true, but unfortunately not every VCS is as denormalized data-wise as Git is. Hg records rename info and a manifest of changed files in the changeset explicitly, whereas Git figures them out from the linked trees. This means that if some plugin does not write the file listing or rename info properly, it's difficult to recreate perfectly. It also doesn't help that the method that writes that changed-file list from contents in memory operates subtly differently than the one that writes it from files in the working directory. This caused days of headaches for me trying to keep bidirectional losslessness. Possibly not terribly helpful information, but interesting to me nonetheless. Scott