Re: Bug report: "Use of uninitialized value $_ in print"

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 2, 2018, 17:48 UTC
Message-ID: <xmqqefl2cqsd.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20180302104232.GA11074@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

> Unfortunately, I don't think there's an easy way to do what you want
> (show word-diffs but apply the full diff).

The current "word-diff" discards the information on where the lines end, and it is pretty much hopeless/useless in the context of "add -p". It would be a good addition to revamp it so that it keeps the original lines in pre/post images but only colors/highlights the byte ranges in such a way that (1) on a pre-image line, paint only the byte range that do not appear in the post-image, and (2) on a post-image line, paint only the byte range that do not appear in the pre-image.

E.g. Given these two

    diff --git a/1 b/2
    index aa49234b68..1cd9f6b5fd 100644
    --- a/1
    +++ b/2
    @@ -1,2 +1 @@
    -a b c e
    -f g i j
    +a b d f g h

the current word-diff would give (I cannot do colors here, so I'll upcase the colored letters):

    @@ -1,2 +1 @@
    a b C ED f g I JH

as the output, but if we produced

    @@ -1,2 +1 @@
    -a b C E
    -f g I J
    +a b D f g H

instead, then colored "add -p" would become easier to see.

And that would be useful outside the context of "add -p", which is a huge plus.