Re: [PATCH] ref-filter: don't look for objects when outside of a repository

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

Jeff King <peff@peff.net> writes:

> On Thu, Nov 15, 2018 at 04:38:44AM -0500, Jeff King wrote:
>
>> Is SOURCE_NONE a complete match for what we want?
>> 
>> I see problems in both directions:
>> 
>>  - sorting by "objectname" works now, but it's marked with SOURCE_OBJ,
>>    and would be forbidden with your patch.  I'm actually not sure if
>>    SOURCE_OBJ is accurate; we shouldn't need to access the object to
>>    show it (and we are probably wasting effort loading the full contents
>>    for tools like for-each-ref).
>> 
>>    However, that's not the full story. For objectname:short, it _does_ call
>>    find_unique_abbrev(). So we expect to have an object directory.
>
> Oops, I'm apparently bad at reading. It is in fact SOURCE_OTHER, which
> makes sense (outside of this whole "--sort outside a repo thing").
>
> But we'd ideally distinguish between "objectname" (which should be OK
> outside a repo) and "objectname:short" (which currently segfaults).

Arguably, use of ref-filter machinery in ls-remote, whether it is
given from inside or outside a repo, was a mistake in 1fb20dfd
("ls-remote: create '--sort' option", 2018-04-09), as the whole
point of "ls-remote" is to peek the list of refs and it is perfectly
normal that the objects listed are not available.

"ls-remote --sort=authorname" that is run in a repository may not
segfault on a ref that points at a yet-to-be-fetched commit, but it
cannot be doing anything sensible.  Is it still better to silently
produce a nonsense result than refusing to --sort no matter what the
sort keys are, whether we are inside or outside a repository?