Jakub Narębski <jnareb@xxxxxxxxx> 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.