git@vger.kernel.org list mirror (unofficial, one of many)
 help / color / mirror / code / Atom feed
From: Jeff King <peff@peff.net>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
	Derrick Stolee <derrickstolee@github.com>,
	Elijah Newren <newren@gmail.com>
Subject: Re: [PATCH v3 0/4] add and apply a rule to find "unused" init+free
Date: Fri, 1 Jul 2022 14:09:46 -0400	[thread overview]
Message-ID: <Yr84aglgBwIvnwC7@coredump.intra.peff.net> (raw)
In-Reply-To: <cover-v3-0.4-00000000000-20220701T102506Z-avarab@gmail.com>

On Fri, Jul 01, 2022 at 12:30:55PM +0200, Ævar Arnfjörð Bjarmason wrote:

> This series adds a coccinelle rule to find and remove code where the
> only reference to a variable in a given function is to malloc() &
> free() it, where "malloc" and "free" also match
> "strbuf_init/strbuf_release", and then later in the series anything
> that looks like a init/free pattern.

Overall, I hated this much less than I expected to. ;)

My main concern was that we'd have a jumble of init/release rules for
every data type, but the regex matching on identifier names lets us do
things broadly. And for data types that don't match our usual naming
conventions, that seems like a good opportunity to consider changing
their names.

I'm not too concerned about false positives here, since there are humans
in the loop. The resulting diffs are pretty obvious to review, and a
compiler would obviously catch any case where the variable really did
get used in between.

I do wish we could do it with the compiler and not coccinelle, just
because the latter has been such a source of frustration in terms of
performance issues and head-scratching "why didn't it catch this one"
cases. But this is IMHO much better than nothing, as shown by the
cleanups it already found.

-Peff

  parent reply	other threads:[~2022-07-01 18:12 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-20 11:57 [PATCH] cocci: add and apply a rule to find "unused" variables Ævar Arnfjörð Bjarmason
2022-06-21 22:44 ` [PATCH v2 0/2] add and apply a rule to find "unused" init+free Ævar Arnfjörð Bjarmason
2022-06-21 22:44   ` [PATCH v2 1/2] cocci: add and apply a rule to find "unused" variables Ævar Arnfjörð Bjarmason
2022-06-22 16:02     ` Junio C Hamano
2022-06-21 22:44   ` [PATCH v2 2/2] cocci: remove "when strict" from unused.cocci Ævar Arnfjörð Bjarmason
2022-07-01 10:30   ` [PATCH v3 0/4] add and apply a rule to find "unused" init+free Ævar Arnfjörð Bjarmason
2022-07-01 10:30     ` [PATCH v3 1/4] cocci: add and apply a rule to find "unused" strbufs Ævar Arnfjörð Bjarmason
2022-07-01 18:04       ` Jeff King
2022-07-01 19:55       ` Eric Sunshine
2022-07-01 10:30     ` [PATCH v3 2/4] cocci: catch unused "strbuf" using an xmalloc() pattern Ævar Arnfjörð Bjarmason
2022-07-01 10:30     ` [PATCH v3 3/4] cocci: remove "when strict" from unused.cocci Ævar Arnfjörð Bjarmason
2022-07-01 21:33       ` Eric Sunshine
2022-07-01 10:30     ` [PATCH v3 4/4] cocci: generalize "unused" rule to cover more than "strbuf" Ævar Arnfjörð Bjarmason
2022-07-01 18:09     ` Jeff King [this message]
2022-07-05 13:46     ` [PATCH v4 0/6] add and apply a rule to find "unused" init+free Ævar Arnfjörð Bjarmason
2022-07-05 13:46       ` [PATCH v4 1/6] Makefile: remove mandatory "spatch" arguments from SPATCH_FLAGS Ævar Arnfjörð Bjarmason
2022-07-05 13:46       ` [PATCH v4 2/6] Makefile & .gitignore: ignore & clean "git.res", not "*.res" Ævar Arnfjörð Bjarmason
2022-07-05 13:46       ` [PATCH v4 3/6] cocci: add a "coccicheck-test" target and test *.cocci rules Ævar Arnfjörð Bjarmason
2022-07-05 13:46       ` [PATCH v4 4/6] cocci: have "coccicheck{,-pending}" depend on "coccicheck-test" Ævar Arnfjörð Bjarmason
2022-07-05 13:46       ` [PATCH v4 5/6] cocci: add and apply a rule to find "unused" strbufs Ævar Arnfjörð Bjarmason
2022-07-05 13:47       ` [PATCH v4 6/6] cocci: generalize "unused" rule to cover more than "strbuf" Ævar Arnfjörð Bjarmason
2022-07-06 19:30       ` [PATCH v4 0/6] add and apply a rule to find "unused" init+free Junio C Hamano
2022-07-11  9:41       ` Jeff King
2022-07-11 10:54         ` Ævar Arnfjörð Bjarmason

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

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=Yr84aglgBwIvnwC7@coredump.intra.peff.net \
    --to=peff@peff.net \
    --cc=avarab@gmail.com \
    --cc=derrickstolee@github.com \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    --cc=newren@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.
Code repositories for project(s) associated with this public inbox

	https://80x24.org/mirrors/git.git

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 read-only IMAP folder(s) and NNTP newsgroup(s).