Re: [PATCHv3] attr: convert to new threadsafe API

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

On Tue, Oct 18, 2016 at 4:52 PM, Stefan Beller <sbeller@google.com> wrote:
>
> >
> > By the way, I do see a merit on the "check" side (tl;dr: but I do
> > not think "result" needs it, hence I do not see the need for the
> > "ugly" variants).
>
> So we'd rather go with const char **result instead of our own new struct there.
> Ok, got it.

I do not think you got it. I am talking about wrapping struct around
an array of element,
not each element in the array. IOW

> > If we were still to do the wrapping for result, I would say that
> > basing it around the FLEX_ARRAY idiom, i.e.
> >
> >>         struct git_attr_result {
> >>                 int num_slots;
> >>                 const char *value[FLEX_ARRAY];
> >>         };

the structure around the array of elements (value) that allows us to have
something other than value[] in it. That is what I said "I do not see
the need for".

It is perfectly fine future-proofing to have

struct git_attr_result_value {
  const char *value;
};

and have the users of API declare

struct git_attr_result value[5];

or whatever. That way we could fatten the structure later if we wanted
to without having to update the users of API, and there is no downside.

Having wrapping strut around the array does have a huge downside,
and that is what I said I see no need for.