Re: [PATCH 1/2] diff-lib: simplify do_diff_cache()

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

Jeff King <peff@peff.net> writes:

> On Tue, Jul 19, 2011 at 11:13:05AM -0700, Junio C Hamano wrote:
>
>> Since 34110cd (Make 'unpack_trees()' have a separate source and
>> destination index, 2008-03-06), we can run unpack_trees() without munging
>> the index at all, but do_diff_cache() tried ever so carefully to work
>> around the old behaviour of the function.
>> 
>> We can just tell unpack_trees() not to touch the original index and there
>> is no need to clean-up whatever the previous round has done.
>
> Can we drop the calls to discard_cache in reset.c now?

Possibly, along with "index-was-discarded" flag bit.

> $ git grep -B1 discard_cache builtin/reset.c
> builtin/reset.c-        /* do_diff_cache() mangled the index */
> builtin/reset.c:        discard_cache();
> --
> builtin/reset.c-                /* The index is still clobbered from do_diff_cache() */
> builtin/reset.c:                discard_cache();
>
> -Peff