Re: ancestor and descendant ~ clarification needed

[Xue Fuqiao <xfq.free@gmail.com>]

On Sat, Oct 24, 2015 at 12:56 AM, Junio C Hamano <gitster@pobox.com> wrote:
>> I see.  Thank you.  What do you think about the following minor patch
>> for user-manual.txt?
>
> While the updated text is more correct than the original, I do not
> know if that is sufficient, or we would also want to mention the
> "Already up-to-date!" case here while at it.

I thought about that, and IMHO it's not needed.  The section name is
"Fast-forward merges" and intends to introduce the "fast-forward"
concept, which is irrelevant to "Already up-to-date!".  Although the
"Already up-to-date!" case isn't mentioned all over the manual, it's
pretty clear to me (as someone who isn't quite familiar with Git).

>> -However, if the current branch is a descendant of the other--so every
>> -commit present in the one is already contained in the other--then Git
>> -just performs a "fast-forward"; the head of the current branch is moved
>> -forward to point at the head of the merged-in branch, without any new
>> -commits being created.
>> +However, if the current branch is an ancestor of the other--so every commit
>> +present in the current branch is already contained in the other
>> branch--then Git
>> +just performs a "fast-forward"; the head of the current branch is moved forward
>> +to point at the head of the merged-in branch, without any new commits being
>> +created.