From: Johannes Sixt <j.sixt@viscovery.net>
Date: Fri, 17 Jul 2009 06:38:17 GMT
Subject: Re: [PATCH] Fix rebase -p --onto
Message-ID: <4A601C59.8040108@viscovery.net>
In-Reply-To: <20090716230031.GM7503@vinegar-pot.mit.edu>

Greg Price schrieb:
> In a rebase with --onto, the correct test for whether we can skip
> rewriting a commit is if it is already on top of $ONTO, not $UPSTREAM.
> Without --onto, this distinction does not exist and the behavior does
> not change.
> 
> 
> In the situation
> 
>  X---o---o---o---M
>   \             /
>    x---x---x---x
> 
>  Y
> 
> if we try to move the branches merged at M from their base on X to be
> based on Y, so as to get
> 
>  X
> 
>  Y---o'--o'--o'--M'
>   \             /
>    x'--x'--x'--x'
> 
> then we fail.  The command `git rebase -p --onto Y X M` moves only the
> first-parent chain, like so:
> 
>  X
>   \
>    x---x---x---x
>                 \
>  Y---o'--o'--o'--M'
> 
> because it mistakenly drops the other branch(es) x---x---x---x from
> the TODO file.  This tests and fixes this behavior.

I think the current behavior is by design. There is nothing to fix.

The purpose of rebase -p is to leave non-first children alone and rebase
only the first child parenthood chain. It is not the purpose to reseat an
entire history DAG.

-- Hannes