Subject: Re: [PATCH 3/3] diff: correct warning message when renameLimit exceeded

From: Junio C Hamano <[email-masked]>
Date: Tue, 13 Jul 2021 22:17:16 -0700

Elijah Newren <[email-masked]> writes:

> Am I mixing up negatives/positives (as I'm prone to do), or would it
> be more correct to say the new algorithm risks suboptimal positives
> rather than that it risks false negatives?

I'm prone to mixing them up, too, but I think they are the sides of
the same coin.  Imagine there is a path X on the source side, and
two paths Y and Z on the destination side.  With exhaustive match,
Z might be a better match (content-wise) to X than Y is to X.

For the path X on the source that is matched with a suboptimal
counterpart Y on the destination side, we may call the situation a
false-positive because with a more exhaustive search we might have
been able to find Z that is a better match.  For the path Z on the
destination side that was culled too early with heuristics and
failed to be matched with the source path X that got matched with a
suboptimal destination path Y, it is a loss for Z---it wasn't chosen
when it should have been (i.e. a false negative, as Z saw no
counterparts).

In any case, during the word search for "inexact", "more precise",
"more expensive", I do not think negatives and positives will play a
big role anyway, so...