From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>,
"Phillip Wood" <phillip.wood123@gmail.com>,
"Jeff King" <peff@peff.net>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: [PATCH 0/7] xdiff: use standard alloc macros, share them via git-shared-util.h
Date: Fri, 8 Jul 2022 16:20:12 +0200 [thread overview]
Message-ID: <cover-0.7-00000000000-20220708T140354Z-avarab@gmail.com> (raw)
In-Reply-To: <b34dcb93-df73-f5de-3c7c-7ab6c3250afe@gmail.com>
This series is on top of
https://lore.kernel.org/git/pull.1272.git.1656516334.gitgitgadget@gmail.com/;
and shows that we can factor our the allocation macros used in cache.h
and git-compat-util.h instead of defining replacements for them and
alloc_nr() in xdiff/*.
The journy towards doing so is slightly longer, but I think worth
doing, since...
On Fri, Jul 08 2022, Phillip Wood wrote:
> On 07/07/2022 12:17, Ævar Arnfjörð Bjarmason wrote:
>> I don't think it's more readable to carry code in-tree that's
>> unreachable except when combined with code out-of-tree. I.e. this series
>> leaves us with the equivalent of:
>> ptr = xmalloc(...);
>> if (!ptr)
>> /* unreachable in git.git ... */
>> I don't think it's more readable to have code that rather trivial
>> analysis will show goes against the "__attribute__((noreturn))" we're
>> placing on our die() function.
>
> We're already in this situation. The code in xdiff is written to
> handle allocation failures and we use an allocation function that dies
> instead. This patch series does nothing to alter that situation.
>[...]
>> That just seems inviting a segfault or undefined/untested behavior
>> (whether in the sense of "undefined by C" or "untested by git.git's
>> codebase logic"). Everything around xmalloc() now assumes "never returns
>> NULL", and you want to:
>> * Make it return NULL when combined with out-of-tree-code
>
> No I do not want to alter the behavior of xmalloc() at all, that is
> why this series does not alter the behavior of xmalloc()
> [...]
> I think there is an argument that we should change our xdiff wrapper
> to use malloc() rather than xmalloc() so we're able to test the error
> handling. That then begs the question as to how we actually get the
> allocation functions to fail when they're being tested. I also think
> that is an orthogonal change that could happen with or without this
> patch series.
I think part of what I was claiming upthread I was just confused
about. I.e. yes we do use xdl_malloc() defined as xmalloc() already,
what *is* true (and I didn't make this clear) was that your proposed
series cements that further in place.
But as 6/7 here notes 36c83197249 (xdiff: use xmalloc/xrealloc,
2019-04-11) left us with that state of affairs for expediency, but as
we're really close to just "properly lib-ifying" xdiff I think we
should just do that. At the time of 36c83197249 we had ~20 calls to
xdl_malloc(), after your series we were at ~1/2 of that (including a
callers that 36c83197249 explicitly punted on).
This larger series is something we can do later, but I'm submitting it
as a non-RFC in case there's consensus to pick it up on top. The sum
of the two would be smaller if they were squashed together, but I
haven't done that here.
The 1/7 is an amendmend I suggested to 47be28e51e6 (Merge branch
'pw/xdiff-alloc-fail', 2022-03-09), since it was modifying some of the
same lines of code...
Ævar Arnfjörð Bjarmason (7):
xdiff: simplify freeing patterns around xdl_free_env()
git-shared-util.h: move "shared" allocation utilities here
git-shared-util.h: add G*() versions of *ALLOC_*()
xdiff: use G[C]ALLOC_ARRAY(), not XDL_CALLOC_ARRAY()
xdiff: use GALLOC_GROW(), not XDL_ALLOC_GROW()
xdiff: remove xdl_malloc() wrapper, use malloc(), not xmalloc()
xdiff: remove xdl_free(), use free() instead
cache.h | 75 -----------------------------
git-compat-util.h | 28 ++---------
git-shared-util.h | 115 +++++++++++++++++++++++++++++++++++++++++++++
xdiff/xdiff.h | 5 --
xdiff/xdiffi.c | 47 ++++++++----------
xdiff/xhistogram.c | 15 +++---
xdiff/xmacros.h | 23 ---------
xdiff/xmerge.c | 57 ++++++++++++----------
xdiff/xpatience.c | 14 +++---
xdiff/xprepare.c | 60 +++++++++++++----------
xdiff/xutils.c | 33 ++++---------
xdiff/xutils.h | 2 -
12 files changed, 234 insertions(+), 240 deletions(-)
create mode 100644 git-shared-util.h
--
2.37.0.913.g189dca38629
next prev parent reply other threads:[~2022-07-08 14:20 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-29 15:25 [PATCH 0/3] xdiff: introduce memory allocation macros Phillip Wood via GitGitGadget
2022-06-29 15:25 ` [PATCH 1/3] xdiff: introduce XDL_ALLOC_ARRAY() Phillip Wood via GitGitGadget
2022-06-29 15:25 ` [PATCH 2/3] xdiff: introduce XDL_CALLOC_ARRAY() Phillip Wood via GitGitGadget
2022-06-30 18:17 ` Junio C Hamano
2022-07-06 13:17 ` Phillip Wood
2022-06-29 15:25 ` [PATCH 3/3] xdiff: introduce XDL_ALLOC_GROW() Phillip Wood via GitGitGadget
2022-06-30 10:54 ` Ævar Arnfjörð Bjarmason
2022-06-30 12:03 ` Phillip Wood
2022-06-30 12:38 ` Phillip Wood
2022-06-30 13:25 ` Ævar Arnfjörð Bjarmason
2022-07-06 13:23 ` Phillip Wood
2022-07-07 11:17 ` Ævar Arnfjörð Bjarmason
2022-07-08 9:35 ` Phillip Wood
2022-07-08 14:20 ` Ævar Arnfjörð Bjarmason [this message]
2022-07-08 14:20 ` [PATCH 1/7] xdiff: simplify freeing patterns around xdl_free_env() Ævar Arnfjörð Bjarmason
2022-07-08 14:20 ` [PATCH 2/7] git-shared-util.h: move "shared" allocation utilities here Ævar Arnfjörð Bjarmason
2022-07-08 14:20 ` [PATCH 3/7] git-shared-util.h: add G*() versions of *ALLOC_*() Ævar Arnfjörð Bjarmason
2022-07-11 10:06 ` Phillip Wood
2022-07-08 14:20 ` [PATCH 4/7] xdiff: use G[C]ALLOC_ARRAY(), not XDL_CALLOC_ARRAY() Ævar Arnfjörð Bjarmason
2022-07-11 10:10 ` Phillip Wood
2022-07-08 14:20 ` [PATCH 5/7] xdiff: use GALLOC_GROW(), not XDL_ALLOC_GROW() Ævar Arnfjörð Bjarmason
2022-07-11 10:13 ` Phillip Wood
2022-07-11 10:48 ` Ævar Arnfjörð Bjarmason
2022-07-13 9:09 ` Phillip Wood
2022-07-13 10:48 ` Ævar Arnfjörð Bjarmason
2022-07-13 13:21 ` Phillip Wood
2022-07-08 14:20 ` [PATCH 6/7] xdiff: remove xdl_malloc() wrapper, use malloc(), not xmalloc() Ævar Arnfjörð Bjarmason
2022-07-08 17:42 ` Phillip Wood
2022-07-08 21:44 ` Ævar Arnfjörð Bjarmason
2022-07-08 19:35 ` Jeff King
2022-07-08 21:47 ` Ævar Arnfjörð Bjarmason
2022-07-11 9:33 ` Jeff King
2022-07-08 14:20 ` [PATCH 7/7] xdiff: remove xdl_free(), use free() instead Ævar Arnfjörð Bjarmason
2022-07-08 17:51 ` Phillip Wood
2022-07-08 21:26 ` Ævar Arnfjörð Bjarmason
2022-07-11 9:26 ` Phillip Wood
2022-07-11 9:54 ` Phillip Wood
2022-07-11 10:02 ` Ævar Arnfjörð Bjarmason
2022-07-13 13:00 ` Phillip Wood
2022-07-13 13:18 ` Ævar Arnfjörð Bjarmason
2022-06-30 18:32 ` [PATCH 3/3] xdiff: introduce XDL_ALLOC_GROW() Junio C Hamano
2022-07-06 13:14 ` Phillip Wood
2022-06-30 10:46 ` [PATCH 0/3] xdiff: introduce memory allocation macros Ævar Arnfjörð Bjarmason
2022-07-08 16:25 ` [PATCH v2 0/4] " Phillip Wood via GitGitGadget
2022-07-08 16:25 ` [PATCH v2 1/4] xdiff: introduce XDL_ALLOC_ARRAY() Phillip Wood via GitGitGadget
2022-07-08 16:25 ` [PATCH v2 2/4] xdiff: introduce xdl_calloc Phillip Wood via GitGitGadget
2022-07-08 16:25 ` [PATCH v2 3/4] xdiff: introduce XDL_CALLOC_ARRAY() Phillip Wood via GitGitGadget
2022-07-08 16:25 ` [PATCH v2 4/4] xdiff: introduce XDL_ALLOC_GROW() Phillip Wood via GitGitGadget
2022-07-08 22:17 ` Ævar Arnfjörð Bjarmason
2022-07-11 10:00 ` Phillip Wood
2022-07-12 7:19 ` Jeff King
2022-07-13 9:38 ` Phillip Wood
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=cover-0.7-00000000000-20220708T140354Z-avarab@gmail.com \
--to=avarab@gmail.com \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=peff@peff.net \
--cc=phillip.wood123@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).