From mboxrd@z Thu Jan  1 00:00:00 1970
From: Liu Yubao <yubao.liu@gmail.com>
Subject: Re: two questions about the format of loose object
Date: Tue, 02 Dec 2008 10:19:52 +0800
Message-ID: <49349B48.9050603@gmail.com>
References: <493399B7.5000505@gmail.com>	<7voczws3np.fsf@gitster.siamese.dyndns.org>	<4933AE55.2090007@gmail.com> <m33ah8jfm2.fsf@localhost.localdomain>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Cc: Junio C Hamano <gitster@pobox.com>, git list <git@vger.kernel.org>
To: Jakub Narebski <jnareb@gmail.com>
X-From: git-owner@vger.kernel.org Tue Dec 02 03:21:40 2008
Return-path: <git-owner@vger.kernel.org>
Envelope-to: gcvg-git-2@gmane.org
Received: from vger.kernel.org ([209.132.176.167])
	by lo.gmane.org with esmtp (Exim 4.50)
	id 1L7KtM-0002bE-Fz
	for gcvg-git-2@gmane.org; Tue, 02 Dec 2008 03:21:36 +0100
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752587AbYLBCT7 (ORCPT <rfc822;gcvg-git-2@m.gmane.org>);
	Mon, 1 Dec 2008 21:19:59 -0500
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752371AbYLBCT7
	(ORCPT <rfc822;git-outgoing>); Mon, 1 Dec 2008 21:19:59 -0500
Received: from ti-out-0910.google.com ([209.85.142.184]:55547 "EHLO
	ti-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751555AbYLBCT6 (ORCPT <rfc822;git@vger.kernel.org>);
	Mon, 1 Dec 2008 21:19:58 -0500
Received: by ti-out-0910.google.com with SMTP id b6so1750278tic.23
        for <git@vger.kernel.org>; Mon, 01 Dec 2008 18:19:56 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=gamma;
        h=domainkey-signature:received:received:message-id:date:from
         :user-agent:mime-version:to:cc:subject:references:in-reply-to
         :content-type:content-transfer-encoding;
        bh=hwAadXP+eYenZ7x6M7xbVoezAXJQerawvsQ+yl5Xun8=;
        b=qcn0VgIZzl/KtGpKvnZYzF590URTF9lnnrrht1C7OlWJcmvhxdBQx7gT/y8z4qwrVd
         cdkIZ3pD9NGbI/7i5YLJ7NJuuup5lv+hR5c5D6bhlM46b0fVgXgd27vmHHweVajKnGoh
         gfPAqzSc4OTqpPeFh5pc3h2LPi9dD8Pz8dRMo=
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=message-id:date:from:user-agent:mime-version:to:cc:subject
         :references:in-reply-to:content-type:content-transfer-encoding;
        b=XGIwvOXZidYpbg/dzHX/KJkKf0f5Is+fYZJBDwP4QQDJjBbinI8/PF4xuGnn+VzPuc
         xOpNor7KB3Y+9sSr/GQ61AiBog/i083v5EpkFaqeQrW7wJKiiNhkxnMaM25tJfla2W6S
         ptuXNO4k7/Ynky7wmhF4GFnTMoh1oVXHQudRo=
Received: by 10.110.33.15 with SMTP id g15mr17297357tig.32.1228184396621;
        Mon, 01 Dec 2008 18:19:56 -0800 (PST)
Received: from ?10.64.1.142? ([211.157.41.194])
        by mx.google.com with ESMTPS id w12sm2412748tib.10.2008.12.01.18.19.54
        (version=TLSv1/SSLv3 cipher=RC4-MD5);
        Mon, 01 Dec 2008 18:19:55 -0800 (PST)
User-Agent: Thunderbird 2.0.0.18 (Windows/20081105)
In-Reply-To: <m33ah8jfm2.fsf@localhost.localdomain>
Sender: git-owner@vger.kernel.org
Precedence: bulk
List-ID: <git.vger.kernel.org>
X-Mailing-List: git@vger.kernel.org
Archived-At: <http://permalink.gmane.org/gmane.comp.version-control.git/102102>

Jakub Narebski wrote:
> Liu Yubao <yubao.liu@gmail.com> writes:
> 
>> cons:
>>
>> * old git client can't read loose objects in new format
>>   (People degrade git rarely and old git can read pack files
>>    generated by new git, so it's not a big problem)
> 
> You forgot about "dumb" protocols, namely HTTP and (deprecated) rsync
> (and IIRC also FTP), which doesn't generate packfiles, and would get
> loose object in format intelligible for old clients.
> 
> IIRC this was main reason why core.legacyHeaders = false was abandoned.
> 

The server can keep an old git or set core.uncompressedLooseObject = false.

Even the pack file format can be changed so that forward compatability will
be broken, I think it's unavoidable.

I'm not clear about the story of core.legacyHeaders, I'll dig the mail
list archive.

Thanks for reminding me of the dumb protocols.


Best regards,

Liu Yubao