From: Duy Nguyen <pclouds@gmail.com>
To: Jeff King <peff@peff.net>
Cc: Rasmus Villemoes <rv@rasmusvillemoes.dk>,
Git Mailing List <git@vger.kernel.org>
Subject: Re: [PATCH 4/4] shallow.c: remove useless test
Date: Mon, 5 Dec 2016 19:00:14 +0700 [thread overview]
Message-ID: <CACsJy8DSw_EXojKYXvkkqkbd3fsQJ=hhAb0GCfMYRzK2S3d-3Q@mail.gmail.com> (raw)
In-Reply-To: <20161203052422.hhaj3idboo6r6dz5@sigill.intra.peff.net>
On Sat, Dec 3, 2016 at 12:24 PM, Jeff King <peff@peff.net> wrote:
> On Fri, Dec 02, 2016 at 09:31:04PM +0100, Rasmus Villemoes wrote:
>
>> It seems to be odd to do x=y if x==y. Maybe there's a bug somewhere near
>> this, but as is this is somewhat confusing.
>
> Yeah, this code is definitely wrong, but I'm not sure what it's trying
> to do. This is the first time I've looked at it.
I'm sorry I don't know why it's there either :( The first version that
has this was v3 [1] which still uses "util" pointdf instead of the
commit slab but the logic does not differ much.
This is the place when we "paint" the parent commit with the same
bitmap as the child I mentioned earlier (though I think I mentioned it
backward). You see similar code in the same loop just a bit earlier:
if the commit has not been painted, it gets a new bitmap, otherwise
new refs are OR'd to its bitmap. It's the OR part (when the bitmaps
pointed by *p_refs and *refs differ, it's not just about pointer
comparison) that's probably missing here.
But it looks like we can safely delete the " || *p_refs == *refs" part
because the commit in question is inserted back to the commit list
"head" and revisited in the next iteration. If its bitmap is different
from the child's, then in the next iteration it should hit the "if
(memcmp(tmp, *refs, bitmap_size))" line above, in the same loop, then
the new bit will be added. If it's marked UNINTERESTING though, that
won't happen. I'll need more time to stare at this code...
[1] http://public-inbox.org/git/1385351754-9954-9-git-send-email-pclouds@gmail.com/
--
Duy
next prev parent reply other threads:[~2016-12-05 12:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-02 20:31 [PATCH 1/4] shallow.c: make paint_alloc slightly more robust Rasmus Villemoes
2016-12-02 20:31 ` [PATCH 2/4] shallow.c: avoid theoretical pointer wrap-around Rasmus Villemoes
2016-12-03 5:17 ` Jeff King
2016-12-02 20:31 ` [PATCH 3/4] shallow.c: bit manipulation tweaks Rasmus Villemoes
2016-12-03 5:21 ` Jeff King
2016-12-02 20:31 ` [PATCH 4/4] shallow.c: remove useless test Rasmus Villemoes
2016-12-03 5:24 ` Jeff King
2016-12-05 12:00 ` Duy Nguyen [this message]
2016-12-03 5:14 ` [PATCH 1/4] shallow.c: make paint_alloc slightly more robust Jeff King
2016-12-05 10:02 ` Duy Nguyen
2016-12-06 12:53 ` [PATCH v2 0/6] shallow.c improvements Nguyễn Thái Ngọc Duy
2016-12-06 12:53 ` [PATCH v2 1/6] shallow.c: rename fields in paint_info to better express their purposes Nguyễn Thái Ngọc Duy
2016-12-06 12:53 ` [PATCH v2 2/6] shallow.c: stop abusing COMMIT_SLAB_SIZE for paint_info's memory pools Nguyễn Thái Ngọc Duy
2016-12-06 12:53 ` [PATCH v2 3/6] shallow.c: make paint_alloc slightly more robust Nguyễn Thái Ngọc Duy
2016-12-06 12:53 ` [PATCH v2 4/6] shallow.c: avoid theoretical pointer wrap-around Nguyễn Thái Ngọc Duy
2016-12-06 12:53 ` [PATCH v2 5/6] shallow.c: bit manipulation tweaks Nguyễn Thái Ngọc Duy
2016-12-06 12:53 ` [PATCH v2 6/6] shallow.c: remove useless code Nguyễn Thái Ngọc Duy
2016-12-06 13:42 ` [PATCH v2 0/6] shallow.c improvements Jeff King
2016-12-06 13:47 ` Duy Nguyen
2016-12-07 23:42 ` Junio C Hamano
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