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

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 14, 2021, 05:17 UTC
Message-ID: <xmqq7dhtzd7n.fsf@gitster.g>
In-Reply-To: <CABPp-BFrLd+h0rzkY5nijVLzXh7bUK5t7Go=EY9jZksCeKqQLg@mail.gmail.com>

Elijah Newren <newren@gmail.com> 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...