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From: Junio C Hamano <gitster@pobox.com>
To: Eli Barzilay <eli@barzilay.org>
Cc: "René Scharfe" <l.s.r@web.de>, git <git@vger.kernel.org>
Subject: Re: git-diff bug?
Date: Mon, 02 Nov 2020 14:14:59 -0800	[thread overview]
Message-ID: <xmqqlffjs8ws.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <CALO-gusRt4J5ar45mo7un-EENyt5cX2SQvcXgyMmaHNZg5bFUg@mail.gmail.com> (Eli Barzilay's message of "Mon, 2 Nov 2020 16:06:49 -0500")

Eli Barzilay <eli@barzilay.org> writes:

>> This matches your results.  That the order makes a difference is a bit
>> odd.  Both are valid diffs of the inputs and neither one changes blank
>> lines, though, so it doesn't look like a bug.
>
> How is it valid?

Just this part.  Any patch output that correctly explains how the
preimage text changed to the postimage text is a "valid" diff, and
that is how René used the word.  There are multiple "valid" diff
to bring the preimage to the postimage:

    (preimage)          (postimage)
    aaa                 aaa
    bbb                 bbb
    ccc
                        ccc

In an extreme case, this diff is even valid.

    @@ -1,4 +1,4 @@
    -aaa
    -bbb
    -ccc
    -
    +aaa
    +bbb
    +
    +ccc

It's just that it is not as _useful_ as other valid diff that
explains how the preimage changed to the postimage.

HTH.

  reply	other threads:[~2020-11-02 22:15 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-02  6:53 Eli Barzilay
2020-11-02 17:45 ` René Scharfe
2020-11-02 21:06   ` Eli Barzilay
2020-11-02 22:14     ` Junio C Hamano [this message]
2020-11-03  3:14       ` Eli Barzilay
2020-11-03 16:58         ` Junio C Hamano
2020-11-02 22:00   ` Junio C Hamano

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