Re: Using Origin hashes to improve rebase behavior

[Johan Herland <johan@herland.net>]

On Friday 11 February 2011, skillzero@gmail.com wrote:
> On Thu, Feb 10, 2011 at 1:13 PM, John Wiegley <johnw@boostpro.com> wrote:
> >    a   b   c   3'  d   e*  f
> >    o---o---o---o---o---o---o
> >             \
> >              o---o---o---o
> >              1   2   3   4
> > 
> > At a later date, I want to rebase the private branch onto master.  What
> > will happen is that the changes in 3 will conflict with the rewritten
> > changes in e*.  However, I'd like Git to know that 3 was already
> > incorporated at some earlier time, and *not consider it during the
> > rebase*, since it doesn't need to.
> 
> I don't know very much about how git really works so what I'm saying
> may be dumb, but rather than record where a commit came from, would it
> be reasonable for rebase to look at the patch-id for each change on
> the topic branch after the merge base and automatically remove topic
> branch commits that match that patch-id? So in your example, rebase
> would check each topic branch commit against 3', d, e*, and f and see
> that the 3' patch-id is the same as the topic branch 3 and remove
> topic branch 3 before it gets to e*?

I believe "git rebase" already does exactly what you describe [1].

However, comparing patch-ids stops working when the cherry-pick (3 -> 3') 
has conflicts. IINM, it is the conflicting cases that John is interested in 
solving...


...Johan

[1]: I tested the above scenario, and got no conflicts:

$ git init
$ FOO=a && echo $FOO > $FOO && git add $FOO && git commit -m $FOO
$ FOO=b && echo $FOO > $FOO && git add $FOO && git commit -m $FOO
$ FOO=c && echo $FOO > $FOO && git add $FOO && git commit -m $FOO
$ git checkout -b topic
$ FOO=1 && echo $FOO > $FOO && git add $FOO && git commit -m $FOO
$ FOO=2 && echo $FOO > $FOO && git add $FOO && git commit -m $FOO
$ FOO=3 && echo $FOO > $FOO && git add $FOO && git commit -m $FOO
$ FOO=4 && echo $FOO > $FOO && git add $FOO && git commit -m $FOO
$ git checkout master
$ git cherry-pick topic^
$ FOO=d && echo $FOO > $FOO && git add $FOO && git commit -m $FOO
$ echo e >> 3 && git add 3
$ FOO=e && echo $FOO > $FOO && git add $FOO && git commit -m $FOO
$ FOO=f && echo $FOO > $FOO && git add $FOO && git commit -m $FOO
$ git checkout topic
$ git rebase master
First, rewinding head to replay your work on top of it...
Applying: 1
Applying: 2
Applying: 4
$ # Look, no conflicts.

-- 
Johan Herland, <johan@herland.net>
www.herland.net