Re: [PATCH v1 1/2] reset: don't compute unstaged changes after reset when --quiet

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

Jeff King <peff@peff.net> writes:

> Whereas for the new config variable, you'd probably set it not because
> you want it quiet all the time, but because you want to get some time
> savings. So there it does make sense to me to explain.
>
> Other than that, this seems like an obvious and easy win. It does feel a
> little hacky (you're really losing something in the output, and ideally
> we'd just be able to give that answer quickly), but this may be OK as a
> hack in the interim.

After "git reset --quiet -- this/area/" with this change, any
operation you'd do next that needs to learn if working tree files
are different from what is recorded in the index outside that area
will have to spend more cycles, because the refresh done by "reset"
is now limited to the area.  So if your final goal is "make 'reset'
as fast as possible", this is an obvious and easy win.  For other
goals, i.e. "make the overall experience of using Git feel faster",
it is not so obvious to me, though.

If we somehow know that it is much less important in your setup that
the cached stat bits in the index is kept up to date (e.g. perhaps
you are more heavily relying on fsmonitor and are happy with it),
then I suspect that we could even skip the refreshing altogether and
gain more performance, without sacrificing the "overall experience
of using Git" at all, which would be even better.

> The sad thing is just that it's user-facing, so we have to respect it
> forever. I almost wonder if there should be a global core.optimizeMessages
> or something that tries to tradeoff less information for speed in all
> commands, but makes no promises about which. Then a user with a big repo
> who sets it once will get the benefit as more areas are identified (I
> think "status" already has a similar case with ahead/behind)? And vice
> versa, as some messages get faster to produce, they can be dropped from
> that option.
>
> I dunno. Maybe that is a stupid idea, and people really do want to
> control it on a per-message basis.
>
> -Peff