From mboxrd@z Thu Jan  1 00:00:00 1970
From: Anthony Foiani <anthony.foiani@gmail.com>
Subject: Re: [PATCH] Improve errors from 'git diff --no-index'.
Date: Sun, 22 May 2011 20:35:40 -0600
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To: Junio C Hamano <gitster@pobox.com>
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Junio --

On Sun, May 22, 2011 at 8:14 PM, Junio C Hamano <gitster@pobox.com> wro=
te:
> Anthony Foiani <anthony.foiani@gmail.com> writes:
>
>> I accidentally tried to use "git diff" when I wasn't within a git
>> repository, only to be confused by getting a usage message with no
>> particular error output.
>
> I do not understand this at all.
>
> =C2=A0 =C2=A0$ cd /
> =C2=A0 =C2=A0$ git diff
> =C2=A0 =C2=A0usage: git diff [--no-index] <path> <path>
>
> What's unclear about it?

It's hard for me to explain right now, as I just spent a few hours
figuring out exactly what "git diff" assumed would happen.  And now
that I have done that study, I would not need anything beyond the
original error message, either.

But when I screwed up earlier today, I was somewhat taken aback by the
fact that I kept on getting the same usage message with no indication
of what the heck I was doing wrong:

$ git diff -b main.c
usage: git diff [--no-index] <path> <path>
$ git diff --cached -b main.c
usage: git diff [--no-index] <path> <path>
$ git diff -b HEAD -- main.c
usage: git diff [--no-index] <path> <path>
$ git diff -b -- main.c
usage: git diff [--no-index] <path> <path>

It would have saved me a chunk of time to have one of my diagnostics
(in this case, "not in a git repo") to knock some sense into me
earlier.

*shrug* Toss it in the bit-bucket if you like, but the work's already
been done. And I happen to find the new code more readable than the
previous triple-negative and de Morgan's-expanded conditionals, but
that's of course personal taste.

=46or that matter, the existing code was already doing many of these
checks, but not communicating the results back in any way other than
presenting a usage string. I apparently interpreted that as "you're
calling me wrong", not "you're using me wrong".

There might be a bug even in the previous code, though: there's an odd
early exit from 'path_outside_repo' for absolute pathnames, but I got
lost in the multiple negations and could never quite convince myself
of its correctness (or lack thereof).

Either way, thanks for all your work on git!

Best regards,
Tony