Re: `git blame` Line Number Off-by-one

From: Jeff King <peff@peff.net>
Date: Aug 7, 2020, 22:26 UTC
Message-ID: <20200807222630.GA3750245@coredump.intra.peff.net>
In-Reply-To: <xmqq7duaf6xk.fsf@gitster.c.googlers.com>

On Fri, Aug 07, 2020 at 03:05:27PM -0700, Junio C Hamano wrote:

Show 12 quoted lines

> Jeff King <peff@peff.net> writes:
> 
> > Dropping it entirely, as below, doesn't break any tests. Junio, do you
> > know of a case this is meant to improve?
> 
> I think the only conceivable case is that in the middle of a single
> block of text in an ancient version, another block of lines gets
> inserted during the evolution of the file, but in the end these
> intermediate edits all go away and the same original text remains.
> 
> In such a case, without coalescing, we would not treat the original
> single block of text as a single unit.

Yeah, that makes sense, and it should be possible to construct a case based on that.

> IIRC, blame has some threshold that makes too small a block not
> subject to move and copy detection, and it is most likely to avoid
> fragmenting the blocks too small.

I don't know if that would matter here, though. This coalescing is taking place after all of the blaming has happened, and is just preparing the final output.

-Peff