Re: [RFC/PATCH] Fix path prefixing in grep_object

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> Jonathan Nieder <jrnieder@gmail.com> writes:
>
>> I think Phil meant that when "git grep" is asked to search within
>> "HEAD:some/path", filenames tacked on at the end should be appended
>> with a '/' separator instead of the usual ':' (e.g.,
>> "HEAD:some/path/inner/path.c", not "HEAD:some/path:inner/path.c").
>
> Ah, OK.
>
> I am not sure if we have a proper hint in the revision parser
> machinery, but it may not be too hard to teach rev-cmdline interface
> to keep that kind of information (i.e. "This tree object name is a
> result of parsing '<tree-ish>:path' syntax").

Actually, having thought about this a bit more, I am no longer sure
if this is even a good idea to begin with.

An output line that begins with HEAD:some/path:inner/path.c from
"git grep" is an answer to this question: find the given pattern in
a tree-ish specified with "HEAD:some/path".

On the other hand, HEAD:some/path/inner/path.c is an answer to a
different question: find the pattern in a tree-ish specified with
"HEAD".  The question may optionally be further qualified with "but
limit the search to some/path".  Both the question and its answer
are more intuitive than the former one.

And we have a nice way to ask that question directly, i.e.

    $ git grep -e pattern HEAD some/path

which can be extended naturally to more than one path, e.g.

    $ git grep -e pattern HEAD some/path another/hierarchy

without having to repeat HEAD: part again for each path.

If the user asked the question of the former form, i.e.

    $ git grep -e pattern HEAD:some/path

there may be a reason why the user wanted to ask it in that
(somewhat strange) way.  I am not 100% sure if it is a good idea to
give an answer to a question different from what the user asked by
internally rewriting the question to

    $ git grep -e pattern HEAD -- some/path

So...