Re: rebase --onto might "loose" commits

From: Nicolas Pitre <nico@cam.org>
Date: Feb 19, 2008, 14:43 UTC
Message-ID: <alpine.LFD.1.00.0802190939240.2732@xanadu.home>
In-Reply-To: <20080219125216.GA10444@atjola.homenet>

On Tue, 19 Feb 2008, Björn Steinbrink wrote:

Show 23 quoted lines

> Hi,
> 
> On 2008.02.19 11:05:40 +0000, Johannes Schindelin wrote:
> > On Tue, 19 Feb 2008, Björn Steinbrink wrote:
> > 
> > > when there's nothing to rebase (ie. upstream..branch is empty), rebase 
> > > fails to find any commits to rebase and correctly says "Nothing to do", 
> > > but when --onto is given, we already did a "reset --hard" to newbase, so 
> > > it already _did_ something.
> > 
> > Yes, it did something.  But if you had that:
> > 
> > A - B - C - D - E
> >   \
> >     F
> > 
> > your HEAD was E, and you said "git rebase --onto F E" what exactly do you
> > want it to do?  There is no commit between E and E, so it rebases
> > _nothing_ onto F.  Which means that F should be your new state.
> 
> Strictly, it's correct, but the "Nothing to do" message is a bit
> misleading (IMHO) and the error message made me think, that it actually
> didn't want to do anything.

Yes, the message should probably be changed in that case.

> I'm a bit unsure about rebase being degraded to a "reset --hard" in this
> case is a good idea. Might be a nice user-protection to make rebase
> abort when there's nothing to rebase and --onto is given. But I don't
> care that much.

The "reset --hard" in that case is really the correct behavior. Rebase might be used like 'git pull --rebase', and if your local branch contains no commits of your own then the 'git reset --hard' is really what needs to happen.

The "user protection" lives in the reflog.

Nicolas