Subject: Re: Distinguishing FF vs non-FF updates in the reflog?

From: Junio C Hamano <[email-masked]>
Date: Mon, 22 Mar 2021 11:36:10 -0700

Ævar Arnfjörð Bjarmason <[email-masked]> writes:

>> I'm confused.
>>
>> rows[0][1] == "0f3a981cbd5be5f97e9504ab770cd88f988fe820"
>> rows[1][0] == "0f3a981cbd5be5f97e9504ab770cd88f988fe820"
>>
>> they are the same. I don't understand your argument.
>
> Sorry, I mean same = ff update, not the same = non-ff. So I flipped
> those around in describing it.

I am confused too.  Are you tacking something else, a gap in a run
of reflog entries?  If I go from commit A to B to C, the first log
entry would record the transtion from A->B, and the second entry
would record the transition from B->C, and the lack of gap does not
say anything about the relationship between A and B, or B and C.  A
can be, and does not have to be, an ancestor of B, and B can be, and
does not have to be, an ancestor of C.  Hopping from A to B to C would
leave the same pair of reflog records and I do not think you can tell
the reachability among A and B and C from them.