Re: [RFC/PATCH] core.abbrev doc: document and test the abbreviation length

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

Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:

> @@ -773,6 +773,14 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
>  					return 1;
>  				continue;
>  			}
> +			if (opt_with_value(arg, "--abbrev-len", &arg)) {
> +				unsigned long v;
> +				if (!git_parse_ulong(arg, &v))
> +					return 1;
> +				int len = abbrev_length_for_object_count(v);
> +				printf("%d\n", len);
> +				continue;
> +			}

Instead of exposing this pretty-much "test-only" feature as a new
option to t/helper/test-tool, I think it is OK, if not even better,
to have it in rev-parse proper like this patch does.

I however have a mildly strong suspition that people would expect
"rev-parse --abbrev-len=<num>" to be a synonym of "--short=<num>"

As this is pretty-much a test-only option, perhaps going longer but
more descriptive would make sense?  

	git rev-parse --compute-abbrev-length-for <object-count>

may be an overkill, but something along those lines.

Oh by the way, the code has decl-after-stmt, and perhaps len needs
to be of type "const int" ;-)