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From: Matthijs Kooijman <matthijs@stdin.nl>
To: Junio C Hamano <gitster@pobox.com>
Cc: Duy Nguyen <pclouds@gmail.com>,
	Jonathan Nieder <jrnieder@gmail.com>,
	Stefan Beller <stefanbeller@googlemail.com>,
	schlotter@users.sourceforge.net, Ralf.Wildenhues@gmx.de,
	git@vger.kernel.org
Subject: Re: [PATCH] git clone depth of 0 not possible.
Date: Thu, 30 May 2013 10:23:22 +0200	[thread overview]
Message-ID: <20130530082322.GW25742@login.drsnuggles.stderr.nl> (raw)
In-Reply-To: <7va9nf2fyp.fsf@alter.siamese.dyndns.org>

Hi Junio,

On Tue, May 28, 2013 at 10:04:46AM -0700, Junio C Hamano wrote:
> Matthijs Kooijman <matthijs@stdin.nl> writes:
> 
> > Did you consider how to implement this? Looking at the code, it seems
> > the "deepen" parameter in the wire protocol now means:
> >  - 0: Do not change anything about the shallowness (i.e., fetch
> >    everything from the shallow root to the tip).
> >  - > 0: Create new shallow commits at depth commits below the tip (so
> >    depth == 1 means tip and one below).
> >  - INFINITE_DEPTH (0x7fffffff): Remove all shallowness and fetch
> >    complete history.
> >
> > Given this, I'm not sure how one can express "fetch the tip and nothing
> > below that", since depth == 0 already has a different meaning.
> 
> Doing it "correctly" (in the shorter term) would involve:

Given below suggestion, I take it you don't like what Jonathan proposed
(changing the meaning of the deepen parameter in the protocol so that
the server effectively decides how to interpret --depth)?

>  - adding a capability on the sending side "fixed-off-by-one-depth"
>    to the protocol, and teaching the sending side to advertise the
>    capability;
>    
>  - teaching the sending side to see if the new behaviour to fix
>    off-by-one is asked by the requestor, and stop at the correct
>    number of commits, not oversending one more.  Otherwise retain
>    the old behaviour.
We can implement these two in current git already, since they only
add to the protocol, not break it in an incompatible manner, right?

>  - teaching the requestor that got --depth=N from the end user to
>    pay attention to the new capability in such a way that:
> 
>    - when talking to an old sender (i.e. without the off-by-one
>      fix), send N-1 for N greater than 1.  Punt on N==1;
> 
>    - when talking to a fixed sender, ask to enable the capability,
>      and send N as is (including N==1).
And these should wait for git2, since they change the meaning of the
--depth parameter? Or is this change ok for current git as well?

What do you mean by "punt" exactly? Show an error to the user, saying
only depth >= 2 is supported?

> In the longer term, I think we should introduce a better deepening
> mechanism.  Cf.
Even when there will be a better deepening mechanism, the above is still
useful (passing --depth=1 serves to get just a single commit without
history, which is a distinct usecase from deepening the history of an
existing shallow repository). In other words, I think the "improved
deepening" and "fixed depth" should be complementary features.

Gr.

Matthijs

  reply	other threads:[~2013-05-30  8:23 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-07 18:06 Stefan Beller
2013-01-07 18:06 ` [PATCH] Documentation on depth option in git clone Stefan Beller
2013-01-08  6:28 ` [PATCH] git clone depth of 0 not possible Jonathan Nieder
2013-01-08  6:54   ` Junio C Hamano
2013-01-08  7:36     ` Junio C Hamano
2013-01-08  8:19       ` Junio C Hamano
2013-01-08 14:28       ` Duy Nguyen
2013-01-08 14:32         ` Stefan Beller
2013-01-08 14:45           ` Duy Nguyen
2013-01-08 17:24           ` Junio C Hamano
2013-01-08  7:38     ` Duy Nguyen
2013-01-08  8:05       ` Junio C Hamano
2013-05-28  9:18         ` Matthijs Kooijman
2013-05-28 16:28           ` Jonathan Nieder
2013-05-28 16:31             ` Jonathan Nieder
2013-05-28 16:34             ` Matthijs Kooijman
2013-05-28 16:58               ` Jonathan Nieder
2013-05-28 17:04           ` Junio C Hamano
2013-05-30  8:23             ` Matthijs Kooijman [this message]
2013-06-02 19:14               ` Junio C Hamano
2013-07-09 13:35             ` Matthijs Kooijman
2013-07-11 10:57               ` Matthijs Kooijman
2013-07-11 11:25                 ` [PATCH 1/3] upload-pack: Remove a piece of dead code Matthijs Kooijman
2013-07-11 11:25                   ` [PATCH 2/3] upload-pack: Introduce new "fixed-off-by-one-depth" server feature Matthijs Kooijman
2013-07-11 11:25                   ` [PATCH 3/3] fetch-pack: Request fixed-off-by-one-depth when available Matthijs Kooijman
2013-07-11 12:08                   ` [PATCH 1/3] upload-pack: Remove a piece of dead code Duy Nguyen
2013-07-11 15:49                     ` Junio C Hamano
2013-01-08  7:33 ` [PATCH] git clone depth of 0 not possible Duy Nguyen
2013-01-08  7:37   ` Junio C Hamano

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