Re: [RFC/PATCH 2/3] simplify-merges: never remove all TREESAME parents

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 28, 2013, 18:09 UTC
Message-ID: <7va9oisf1k.fsf@alter.siamese.dyndns.org>
In-Reply-To: <517CCB57.3060807@bracey.fi>

Kevin Bracey <kevin@bracey.fi> writes:

Show 14 quoted lines

>> Could you explain here a bit more the reason why we do not want to
>> remove them and why "-s ours" is so significant that it deserves to
>> be singled out?  And why randomly picking one that is redundant
>> (because it is an ancestor of some other parent) is an improvement?
>
> I feel it's consistent with the default non-full-history
> behaviour. The parent that we choose not to remove is the  same one
> that the default log with "simplify_history==1" would have followed:
> the first parent we are TREESAME to. Or at least that's the intent. So
> this parent would normally be singled out, and it's not an arbitrary
> (or "random") choice.
>
> It feels wrong to me that --full-history --simplify-merges could
> produce a disjoint history from the default.

Finally ;-) That "avoid creating a disjoint history" is the "why we do not want to remove them" I wanted to see in the same comment.

> But this patch as it stands was an "easy" change to make with clearly
> limited scope and relatively little risk - I specifically wanted just
> to include our default "simple" parent.

Yeah, I think it all makes sense.