Re: Change set based shallow clone

From: Jon Smirl <jonsmirl@gmail.com>
Date: Sep 7, 2006, 20:41 UTC
Message-ID: <9e4733910609071341u7e430214j71ddcbefa26810ca@mail.gmail.com>
In-Reply-To: <edpuut$dns$1@sea.gmane.org>

On 9/7/06, Jakub Narebski <jnareb@gmail.com> wrote:

> I don't understand. Git is _not_ patchset based (like GNU Arch, or

I meant change set to refer to a commit plus trees plus blobs that make it up. These may be present in full or delta form.

Show 12 quoted lines

> Mercurial, or CVS). It is snapshot based. So if you want to download
> "skip", you need only for the local part of doenloader to make appropriate
> grafts, like below
>
>
>  *--*--*--*--*--*--*--*--*--*--*--HEAD    (server)
>
>  *--*--*...........*--*--*--*--*--HEAD    (shallow/sparse clone)
>
> But the part you were talking about is _easy_ part; the hard part is
> merges including merging branch which was split off the trunk before
> cutoff-point, history rewriting (c.f. 'pu' branch, and rebases), etc.

Does an average user do these things? The shallow clone is there to address the casual user who gags at a five hour download to get an initial check out Mozilla when they want to make a five line change or just browse the source for a few minutes.

I would expect advanced users to have a full tree present.

I was going to have the dangling references from the shallow clone point to 'not-present' objects. When you try to do any of the more complex operations you would hit these objects and fault down more of the tree.

There would also be a command to bring down all of the objects to fully populate a sparse tree. You could do the shallow clone to begin with and then do the full tree populate overnight or in the background.

Maybe the answer is to build a shallow clone tool for casual use, and then if you try to run anything too complex on it git just tells you that you have to download the entire tree.

-- 
Jon Smirl
jonsmirl@gmail.com