Re: [BUG] redundant error message

From: Junio C Hamano <gitster@pobox.com>
Date: Dec 5, 2013, 20:15 UTC
Message-ID: <xmqqfvq73vhw.fsf@gitster.dls.corp.google.com>
In-Reply-To: <20131205200306.GA13443@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 20 quoted lines

> On Thu, Dec 05, 2013 at 12:00:16PM -0800, Junio C Hamano wrote:
>
>> Jeff King <peff@peff.net> writes:
>> 
>> >   $ >foobar
>> >   $ git rev-parse foobar --
>> >   foobar
>> >   --
>> >   fatal: bad flag '--' used after filename
>> >
>> > That's not right.
>> 
>> Hmph, it looks like it is following the usual "zero-or-more dashed
>> options, zero-or-more revs and then zero-or-one double-dash and then
>> zero-or-more paths" rule to parse the thing.  "foobar" is a file and
>> not a rev, so "--" should not be there, no?
>> 
>> Confused why you think it is not right...
>
> Because once you say "--", then all ambiguity goes away, no?

But it is tricky (not from implementation but from semantics point of view) to make rev-parse follow that "-- separates revs and paths" rule literally. The primary use of rev-parse is to convert revs in extended SHA-1 expressions into concrete object names, so that scripts do not have to worry about having to deal with object names in a format that is not 40-hexdecimal. "git rev-parse foobar --" that gives

	foobar
        --

without any error, because 'foobar' cannot be made into an object name, would be behaving in a way unexpected by the calling script, no?