Re: git log -S or -G

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 8, 2018, 23:09 UTC
Message-ID: <xmqq8t38t4r7.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <alpine.DEB.2.21.1810070719200.2347@hadrien>

Julia Lawall <julia.lawall@lip6.fr> writes:

Show 7 quoted lines

>> Doing the same for -S is much harder at the machinery level, as it
>> performs its thing without internally running "diff" twice, but just
>> counts the number of occurrences of 'foo'---that is sufficient for
>> its intended use, and more efficient.
>
> There is still the question of whether the number of occurrences of foo
> decreases or increases.

Hmph, taking the changes that makes the number of hits decrease would catch a subset of "changes that removes 'foo' only---I am not interested in the ones that adds 'foo'". It will avoid getting confused by a change that moves an existing 'foo' to another place in the same file (as the number of hits does not change), but at the same time, it will miss a change that genuinely removes an existing 'foo' and happens to add a 'foo' at a different place in the same file that is unrelated to the original 'foo'. Depending on the definition of "I am only interested in removed ones", that may or may not be acceptable.