Re: [PATCH 2/9] fsck_tree(): fix shadowed variable

From: Jeff King <peff@peff.net>
Date: May 3, 2021, 20:13 UTC
Message-ID: <YJBZYt8ivlTDHpRM@coredump.intra.peff.net>
In-Reply-To: <87y2cwvz9e.fsf@evledraar.gmail.com>

On Mon, May 03, 2021 at 01:15:03PM +0200, Ævar Arnfjörð Bjarmason wrote:

Show 9 quoted lines

> > Commit b2f2039c2b (fsck: accept an oid instead of a "struct tree" for
> > fsck_tree(), 2019-10-18) introduced a new "oid" parameter to
> > fsck_tree(), and we pass it to the report() function when we find
> [...]
> 
> Have you considered just passing down the "obj" instead of the "oid"?
> It's a bit of a bigger change, but seems to be worth it in this case as
> the below diff (on top of master) shows. We spend quite a bit of effort
> peeling an "obj" just to pass oid/type further down the stack.

That would be undoing the point of the referenced commit above. More discussion in this thread:

  https://lore.kernel.org/git/20191018044103.GA17625@sigill.intra.peff.net/

but the gist is:

  - there were bugs caused by looking at the object structs; not having
    it make sure we can't introduce similar bugs

  - using oids and buffers makes it possible for code to avoid having
    object structs at all. index-pack could take advantage of this (to
    reduce memory usage), but nobody has yet written that patch.

-Peff