Hi Junio,

On Thu, 1 Sep 2016, Junio C Hamano wrote:

> Jakub Narębski <jnareb@gmail.com> writes:
> 
> > I wonder how probable is situation where we save instruction sheet
> > for interactive rebase, with shortened SHA-1, and during rebase
> > shortened SHA-1 stops being unambiguous...
> 
> It is my understanding that the shortened ones are only for end-user
> consumption.  The insn sheet internally uses fully expanded form for
> this exact reason, and then abbreviated back at each step before the
> updated one is presented to the end-user.  Uniqueness guarantee is
> enforced with new objects created during each step taken into
> account by doing it this way.

Indeed, the rebase -i shortens the SHA-1s just before letting the user
edit git-rebase-todo and then expands them back.

Ciao,
Dscho