Re: git-reset and clones

From: Jon Loeliger <jdl@freescale.com>
Date: Mar 17, 2006, 19:19 UTC
Message-ID: <1142623141.17536.225.camel@cashmere.sps.mot.com>
In-Reply-To: <7v4q1x95yo.fsf@assigned-by-dhcp.cox.net>

On Thu, 2006-03-16 at 20:10, Junio C Hamano wrote:

Show 36 quoted lines

> 
> You used to have something like this:
> 
> 
>                  o---o---o---A
>                 /            ^ your HEAD used to point at here
>     ---o---o---o
> 
> and you forgot other people already have the commit chain up to
> commit A.   But you rewound and did cleanups:
> 
>                  o---o---o---A
>                 /
>     ---o---o---o---o---o---B
>                            ^ your HEAD now points at here
> 
> People who track your HEAD have A and your updated head B does
> not fast forward.  Oops.
> 
> The recovery consists of two steps.  The first step is more
> important.  To find what commits you lost that others already
> may have.  You may be lucky and remember A's commit object name,
> but when I did that I had to ask around on the list X-<.
> 
> The second step is a single command:
> 
> 	$ git merge -s ours 'Graft the lost side branch back in' \
> 		HEAD A
> 
> where A is the object name of that commit.  On your current
> branch, this creates a merge commit between A and B (your
> current HEAD), taking the tree object from B.
> 
>                  o---o---o---A
>                 /             \
>     ---o---o---o---o---o---B---M

Junio,

Can you explain a bit more why the "ours" strategy comes into play here? I _think_ I understand, but I'd like to hear a bit more explanation, please. How is this different from just merging in A directly?

> You want to keep the contents of the cleaned-up HEAD, so that is
> why you are taking the tree from B.

And the "ours" strategy effectively says, "Favor the B side of things when pulling in the A parts", right?

>   With this commit M, you are
> telling the outside world that it is OK if they start from a
> commit on the now-recovered side branch.

This is mystical to me. How is the "A" (ie, side branch) now in a "recovered" state?

Thanks, jdl