From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Parkins Subject: Re: [REVISED PATCH 2/6] Introduce commit notes Date: Thu, 19 Jul 2007 11:58:36 +0100 Message-ID: <200707191158.37713.andyparkins@gmail.com> References: <7vfy3l3rj0.fsf@assigned-by-dhcp.cox.net> <7vodi83fg7.fsf@assigned-by-dhcp.cox.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: Junio C Hamano , Linus Torvalds , Johannes Schindelin , Alberto Bertogli , Johan Herland To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Thu Jul 19 12:58:56 2007 Return-path: Envelope-to: gcvg-git@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1IBTih-0004bH-Lj for gcvg-git@gmane.org; Thu, 19 Jul 2007 12:58:56 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757126AbXGSK6n (ORCPT ); Thu, 19 Jul 2007 06:58:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759499AbXGSK6n (ORCPT ); Thu, 19 Jul 2007 06:58:43 -0400 Received: from ug-out-1314.google.com ([66.249.92.168]:3980 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757126AbXGSK6m (ORCPT ); Thu, 19 Jul 2007 06:58:42 -0400 Received: by ug-out-1314.google.com with SMTP id j3so382685ugf for ; Thu, 19 Jul 2007 03:58:41 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:from:to:subject:date:user-agent:cc:references:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:message-id; b=ZxIYwr0nsxEQ3MkGPjzsorL5n7Fsa9ktz4Ae56dnT44unhgxiatH50kbKuDtu9GuXgHwXnJcy3DVJIWA13th6xYz0lBqSF4qOQCqmNp2BAI+q9RCO3I6KwURu+NKyuWwR5bRndzgXmJdKChzpNWJjlFkfBQktTcCokHM2poj2ws= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:from:to:subject:date:user-agent:cc:references:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:message-id; b=hYj0k9KnTNa0z1A3AOOK46SeW6p9sdliBn9oQ0L9gKyldb9sXtcmSrVsu95M2lt2rnTjjgs//j4Ws2M4AUqi1c2eHuuF4C+mXUoqrcFy2OJvjt00TWJWFAyedRQqvdD+71tCyUq9kbQsEDpMHZW/43n/e/+EVU2xp/ILsDcjmGs= Received: by 10.67.119.9 with SMTP id w9mr1088272ugm.1184842721180; Thu, 19 Jul 2007 03:58:41 -0700 (PDT) Received: from dvr.360vision.com ( [194.70.53.227]) by mx.google.com with ESMTPS id z37sm3414554ikz.2007.07.19.03.58.39 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 19 Jul 2007 03:58:40 -0700 (PDT) User-Agent: KMail/1.9.7 In-Reply-To: <7vodi83fg7.fsf@assigned-by-dhcp.cox.net> Content-Disposition: inline Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: On Thursday 2007 July 19, Junio C Hamano wrote: > I've long time ago concluded that if we care about reliability > (and we do very much), a bisectable tree without breaking > backward compatibility is impossible. I was hoping to find a > "hole" in tree object format so that I can place an extended In the case of the notes system, is there not a big hole available because the layout is under tight control? 100644 blob 24631df5c6fceef7f0859903397d81f99a723197 __notes_index 040000 tree dd3f40129c8731b1bdce1d3939de3cdc24a87783 00 040000 tree 2b25612b5d8ee9ef469e72bbf74eab0ec00ae87f 01 In fact, this technique would work for normal tree objects too, except that you'd have to be willing to pick some blob name that would always be the first entry in every tree object, and would never clash with a real file in the tree. Speaking off the top of my head, anything with "/" in it would be an invalid name so 100644 blob 24631df5c6fceef7f0859903397d81f99a723197 /tree_index 040000 tree dd3f40129c8731b1bdce1d3939de3cdc24a87783 00 040000 tree 2b25612b5d8ee9ef469e72bbf74eab0ec00ae87f 01 Would be an easy one to special case, and would be guaranteed not to clash with a file in the tree. Just an idea. I would imagine it's as daft as all my others :-) Andy -- Dr Andy Parkins, M Eng (hons), MIET andyparkins@gmail.com