From: Jeff King <peff@peff•net>
To: Collin Funk <collin.funk1@gmail•com>
Cc: Junio C Hamano <gitster@pobox•com>,
Karthik Nayak <karthik.188@gmail•com>,
shejialuo <shejialuo@gmail•com>,
git@vger•kernel.org, Patrick Steinhardt <ps@pks•im>
Subject: Re: [PATCH v2 2/4] string-list: replace negative index encoding with "exact_match" parameter
Date: Thu, 9 Oct 2025 01:55:54 -0400 [thread overview]
Message-ID: <20251009055554.GD1614343@coredump.intra.peff.net> (raw)
In-Reply-To: <87jz16dux5.fsf@gmail.com>
On Tue, Oct 07, 2025 at 06:49:42PM -0700, Collin Funk wrote:
> In GNU Coreutils and Gnulib we often use 'idx_t', which is a typedef to
> the standard signed type 'ptrdiff_t', when we refer to allocation of
> objects or indexes.
>
> The rational is written in the header file where it is defined [1].
> However, I want to highlight one part that I find most useful:
>
> * Security: Signed types can be checked for overflow via
> '-fsanitize=undefined', but unsigned types cannot.
>
> On common platforms, you will never need to allocate more memory than
> PTRDIFF_MAX anyways:
>
> $ numfmt --to=iec-i `echo $(((1 << 63) - 1))`
> 8.0Ei
>
> I think that addresses Jeff's point that 'int' is too small, which I
> agree with.
Yeah, absolutely. I do not love size_t (and certainly switching signed
"int" to unsigned "size_t" is an easy way to introduce bugs when you
cross the "0" boundary). I'd be very happy with everything using
something like ptrdiff_t, and even hiding it behind idx_t or count_t or
whatever.
-Peff
next prev parent reply other threads:[~2025-10-09 5:55 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-07 16:40 [PATCH 0/4] enhance string-list API to fix sign compare warnings shejialuo
2025-09-07 16:42 ` [PATCH 1/4] string-list: allow passing NULL for `get_entry_index` shejialuo
2025-09-09 6:22 ` Patrick Steinhardt
2025-09-07 16:42 ` [PATCH 2/4] string-list: replace negative index encoding with "exact_match" parameter shejialuo
2025-09-09 6:22 ` Patrick Steinhardt
2025-09-15 12:11 ` shejialuo
2025-09-07 16:42 ` [PATCH 3/4] string-list: change "string_list_find_insert_index" return type to "size_t" shejialuo
2025-09-09 6:23 ` Patrick Steinhardt
2025-09-09 19:21 ` Junio C Hamano
2025-09-10 4:57 ` Patrick Steinhardt
2025-09-07 16:42 ` [PATCH 4/4] refs: enable sign compare warnings check shejialuo
2025-09-09 6:23 ` Patrick Steinhardt
2025-09-07 16:43 ` [PATCH 0/4] enhance string-list API to fix sign compare warnings shejialuo
2025-09-17 9:18 ` [PATCH v2 " shejialuo
2025-09-17 9:19 ` [PATCH v2 1/4] string-list: use bool instead of int for "exact_match" shejialuo
2025-09-17 9:19 ` [PATCH v2 2/4] string-list: replace negative index encoding with "exact_match" parameter shejialuo
2025-09-23 8:14 ` Patrick Steinhardt
2025-10-05 13:31 ` shejialuo
2025-09-23 9:35 ` Karthik Nayak
2025-09-23 18:48 ` Junio C Hamano
2025-09-24 5:36 ` Jeff King
2025-09-24 13:20 ` Junio C Hamano
2025-09-25 2:50 ` Jeff King
2025-09-25 13:33 ` Junio C Hamano
2025-10-09 5:52 ` Jeff King
2025-10-08 1:49 ` Collin Funk
2025-10-09 5:55 ` Jeff King [this message]
2025-10-05 14:11 ` shejialuo
2025-10-05 14:06 ` shejialuo
2025-09-17 9:20 ` [PATCH v2 3/4] string-list: change "string_list_find_insert_index" return type to "size_t" shejialuo
2025-09-23 9:44 ` Karthik Nayak
2025-10-05 9:29 ` shejialuo
2025-09-17 9:20 ` [PATCH v2 4/4] refs: enable sign compare warnings check shejialuo
2025-10-06 6:28 ` [PATCH v3 0/4] enhance string-list API to fix sign compare warnings shejialuo
2025-10-06 6:32 ` [PATCH v3 1/4] string-list: use bool instead of int for "exact_match" shejialuo
2025-10-06 6:32 ` [PATCH v3 2/4] string-list: replace negative index encoding with "exact_match" parameter shejialuo
2025-10-06 6:32 ` [PATCH v3 3/4] string-list: change "string_list_find_insert_index" return type to "size_t" shejialuo
2025-10-09 6:03 ` Jeff King
2025-10-06 6:32 ` [PATCH v3 4/4] refs: enable sign compare warnings check shejialuo
2025-10-06 22:09 ` [PATCH v3 0/4] enhance string-list API to fix sign compare warnings Junio C Hamano
2025-10-08 1:52 ` Collin Funk
2025-10-08 15:56 ` Junio C Hamano
2025-10-08 8:11 ` Karthik Nayak
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=20251009055554.GD1614343@coredump.intra.peff.net \
--to=peff@peff$(echo .)net \
--cc=collin.funk1@gmail$(echo .)com \
--cc=git@vger$(echo .)kernel.org \
--cc=gitster@pobox$(echo .)com \
--cc=karthik.188@gmail$(echo .)com \
--cc=ps@pks$(echo .)im \
--cc=shejialuo@gmail$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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