Re: [RFC/PATCH 0/2] git diff <(command1) <(command2)

From: Junio C Hamano <gitster@pobox.com>
Date: Nov 16, 2016, 18:29 UTC
Message-ID: <xmqqh977qnvk.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <alpine.DEB.2.20.1611161039590.3746@virtualbox>

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

Show 9 quoted lines

> On Mon, 14 Nov 2016, Junio C Hamano wrote:
>
>> I _think_ the no-index mode was primarily for those who want to use
>> our diff as a replacement for GNU and other diffs, and from that
>> point of view, I'd favour not doing the "comparing symbolic link?
>> We'll show the difference between the link contents, not target"
>> under no-index mode myself.
>
> If I read this correctly,...

Now I re-read it and I can see it can be read either way.

By "link contents" in "comparing symbolic link? We'll show the difference between the link contents, not target", I meant the result you get from readlink(2), which will result in

    diff --git a/RelNotes b/RelNotes
    index c02235fe8c..b54330f7cd 120000
    --- a/RelNotes
    +++ b/RelNotes
    @@ -1 +1 @@
    -Documentation/RelNotes/2.10.2.txt
    \ No newline at end of file
    +Documentation/RelNotes/2.11.0.txt
    \ No newline at end of file

not the comparison between the files that are link targets, i.e. hypothetical

    diff --git a/RelNotes b/RelNotes
    index c4d4397023..7a1fce7720 100644
    --- a/Documentation/RelNotes/2.10.2.txt
    +++ b/Documentation/RelNotes/2.11.0.txt
    @@ -1,41 +1,402 @@
    -Git v2.10.2 Release Notes
    -=========================
    +Git 2.11 Release Notes
    ...

And I'd favour *NOT* doing that if we are using our diff as a replacement for GNU and other diffs in "no-index" mode. Which leads to ...

>> That is a lot closer to the diff other people implemented, not ours.
>> Hence the knee-jerk reaction I gave in
>> 
>> http://public-inbox.org/git/xmqqinrt1zcx.fsf@gitster.mtv.corp.google.com

... this conclusion, which is consistent with ...

Show 7 quoted lines

>
> Let me quote the knee-jerk reaction:
>
>> My knee-jerk reaction is:
>>
>>  * The --no-index mode should default to your --follow-symlinks
>>    behaviour, without any option to turn it on or off.

... this one.

But notice "I _think_" in the first sentence you quoted. That is a basic assumption that leads to the conclusion, and that assumption is not a fact. Maybe users do *not* want the "no-index" mode as a replacement for GNU and other diffs, in which case comparing the result of readlink(2) even in no-index mode might have merit. I just didn't think it was the case.