Re: [PATCH 3/3] builtin/grep: allow implicit --no-index

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 11, 2016, 17:26 UTC
Message-ID: <xmqqlh7wxc0y.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20160111111015.GA10612@hank>

Thomas Gummerer <t.gummerer@gmail.com> writes:

Show 22 quoted lines

> On 01/11, Duy Nguyen wrote:
>> On Sun, Jan 10, 2016 at 9:19 PM, Thomas Gummerer <t.gummerer@gmail.com> wrote:
>> > Currently when git grep is used outside of a git repository without the
>> > --no-index option git simply dies.  For convenience, implicitly make git
>> > grep behave like git grep --no-index when it is called outside of a git
>> > repository.
>>
>> Should we have a line about this behavior in git-grep.txt, maybe the
>> description section?
>
> Yes good point, the behavior change should definitely be documented.
>
>> I wonder if anybody wants the old behavior (e.g.
>> non-zero exit code when running outside a repo). If there is such a
>> case (*), we may need an option to revert it back (--no-no-index seems
>> ridiculous, maybe --use-index). The safest way though, is introduce a
>> new option like --use-index=<always|optional|never> then you can make
>> an grep alias with --use-index=optional.
>
> You're right.  I couldn't think of a reason why someone would rely on
> the old behavior, but maybe I missed something.  I like the idea of
> introducing the --use-index=... option.

I don't like that, though ;-)

"We run 'git grep' in random places and relied on it to fail when run in somewhere not under control of Git." feels so flawed at multiple levels that I doubt it deserves to be kept working. For one thing, "git grep" is not the way to tell something is under control of Git (rev-parse would be a better thing for scriptor to use). For another, how would such a script tell between "not a git repository" and there was no hits?

So I do agree that automatic fallback needs to be documented and advertised as a feature (or even a bugfix), I do not think we want to add knobs to keep such a broken script working.

Show 7 quoted lines

> How should we handle priority between --no-index and --use-index,
> should we just give --no-index priority if it is set and ignore the
> new --use-index option, or is there some other way?
>
>> (*) I've been hitting really weird real-world use cases so I'm a bit paranoid..
>> --
>> Duy