From: Jeff King <peff@peff.net>
Date: Wed, 10 Sep 2008 22:55:18 GMT
Subject: Re: [RFC] origin link for cherry-pick and revert
Message-ID: <20080910225518.GA24534@coredump.intra.peff.net>
In-Reply-To: <20080910223427.GB22739@cuci.nl>

On Thu, Sep 11, 2008 at 12:34:27AM +0200, Stephen R. van den Berg wrote:

> I see.  Indeed.  That's a lot better.
> Did the binary search inside tree objects ever get implemented?

I believe it's still linear (and skimming tree-walk.c:find_tree_entry
seems to confirm). However, one advantage of such an approach is that it
will improve as tree lookup improves (e.g., I believe the pack v4 work
included improvements in this area).

> The downsides when doing that are:
> - The lookup cost is small, but still noticable, since it is sometimes
>   done on every commit; using the in-commit origin headerfield solves
>   this at negligible cost.
> - The origin information is no longer cryptographically protected (under
>   certain circumstances this could be considered an advantage and a
>   disadvantage at the same time).

Yes, those are inherent in the scheme, as is the upside that one can
make and distribute such annotations separately from commit creation.

I haven't thought enough about it to decide whether there is a scenario
where making such a "cherry-picked from" annotation might make use of
that property.

-Peff