From: Junio C Hamano <gitster@pobox•com>
To: Jeff King <peff@peff•net>
Cc: Taylor Blau <me@ttaylorr•com>,
git@vger•kernel.org, Elijah Newren <newren@gmail•com>,
Patrick Steinhardt <ps@pks•im>
Subject: Re: [PATCH v3 0/8] hash: introduce unsafe_hash_algo(), drop unsafe_ variants
Date: Wed, 22 Jan 2025 13:31:57 -0800 [thread overview]
Message-ID: <xmqqwmemv8ky.fsf@gitster.g> (raw)
In-Reply-To: <20250118124343.GA3828177@coredump.intra.peff.net> (Jeff King's message of "Sat, 18 Jan 2025 07:43:43 -0500")
Jeff King <peff@peff•net> writes:
> .... But maybe
> returning UNKNOWN (as above) is a safer bet than losing the inverse
> nature of the by_ptr() and by_id() functions, which could otherwise
> cause hard-to-find interactions?
Yeah, that sounds sensible.
> I think it "works" because the backtrace is:
>
> [...]
> #5 0x0000556d436f6b71 in BUG_fl (file=0x556d43790e8b "hash.h", line=324,
> fmt=0x556d43790e73 "null hash, return is %d") at usage.c:335
> #6 0x0000556d4357c2f9 in hash_algo_by_ptr (p=0x0) at /home/peff/compile/git/hash.h:324
> #7 0x0000556d4357c437 in oidclr (oid=0x7ffdf5810ea4, algop=0x0) at /home/peff/compile/git/hash.h:392
> #8 0x0000556d435801c7 in prep_exclude (dir=0x7ffdf5811190, istate=0x556d608959c0, base=0x556d6089da50 "nums",
> baselen=0) at dir.c:1699
> [...]
> #16 0x0000556d4344dd4a in cmd_grep (argc=0, argv=0x556d60895ee8, prefix=0x0, repo=0x0) at builtin/grep.c:1257
>
> So we probably write a totally garbage algo field into the
> object_id, but nobody ever ends up looking at it. Probably
> something we should clean up, but way out of scope for your series.
Yeah, that looks bad, but I think it is fine to leave it outside the
series to fix that.
> But I do think it reinforces that returning UNKNOWN is an
> improvement; it avoids undefined behavior and anybody who tried to
> use it should get a BUG() from calling git_hash_unknown_*()
> functions.
Sounds like a sensitive direction to go in.
Thanks.
next prev parent reply other threads:[~2025-01-22 21:32 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-20 19:13 [PATCH 0/6] hash: introduce unsafe_hash_algo(), drop unsafe_ variants Taylor Blau
2024-11-20 19:13 ` [PATCH 1/6] csum-file: store the hash algorithm as a struct field Taylor Blau
2024-11-21 9:18 ` Jeff King
2024-11-20 19:13 ` [PATCH 2/6] csum-file.c: extract algop from hashfile_checksum_valid() Taylor Blau
2024-11-20 19:13 ` [PATCH 3/6] hash.h: introduce `unsafe_hash_algo()` Taylor Blau
2024-11-21 9:37 ` Jeff King
2024-11-22 0:39 ` brian m. carlson
2024-11-22 8:25 ` Jeff King
2024-11-22 20:37 ` brian m. carlson
2025-01-10 21:38 ` Taylor Blau
2025-01-11 2:45 ` Jeff King
2024-11-20 19:13 ` [PATCH 4/6] csum-file.c: use unsafe_hash_algo() Taylor Blau
2024-11-20 19:13 ` [PATCH 5/6] t/helper/test-hash.c: " Taylor Blau
2024-11-20 19:13 ` [PATCH 6/6] hash.h: drop unsafe_ function variants Taylor Blau
2024-11-21 9:41 ` Jeff King
2025-01-08 19:14 ` [PATCH v2 0/8] hash: introduce unsafe_hash_algo(), drop unsafe_ variants Taylor Blau
2025-01-08 19:14 ` [PATCH v2 1/8] t/helper/test-tool: implement sha1-unsafe helper Taylor Blau
2025-01-08 19:14 ` [PATCH v2 2/8] csum-file: store the hash algorithm as a struct field Taylor Blau
2025-01-16 11:48 ` Patrick Steinhardt
2025-01-17 21:17 ` Taylor Blau
2025-01-08 19:14 ` [PATCH v2 3/8] csum-file.c: extract algop from hashfile_checksum_valid() Taylor Blau
2025-01-08 19:14 ` [PATCH v2 4/8] hash.h: introduce `unsafe_hash_algo()` Taylor Blau
2025-01-16 11:49 ` Patrick Steinhardt
2025-01-17 21:18 ` Taylor Blau
2025-01-08 19:14 ` [PATCH v2 5/8] csum-file.c: use unsafe_hash_algo() Taylor Blau
2025-01-08 19:14 ` [PATCH v2 6/8] t/helper/test-hash.c: " Taylor Blau
2025-01-08 19:14 ` [PATCH v2 7/8] csum-file: introduce hashfile_checkpoint_init() Taylor Blau
2025-01-10 10:37 ` Jeff King
2025-01-10 21:50 ` Taylor Blau
2025-01-17 21:30 ` Taylor Blau
2025-01-18 12:15 ` Jeff King
2025-01-08 19:14 ` [PATCH v2 8/8] hash.h: drop unsafe_ function variants Taylor Blau
2025-01-10 10:41 ` [PATCH v2 0/8] hash: introduce unsafe_hash_algo(), drop unsafe_ variants Jeff King
2025-01-10 21:29 ` Taylor Blau
2025-01-11 2:42 ` Jeff King
2025-01-11 0:14 ` Junio C Hamano
2025-01-11 17:14 ` Taylor Blau
2025-01-17 22:03 ` [PATCH v3 " Taylor Blau
2025-01-17 22:03 ` [PATCH v3 1/8] t/helper/test-tool: implement sha1-unsafe helper Taylor Blau
2025-01-17 22:03 ` [PATCH v3 2/8] csum-file: store the hash algorithm as a struct field Taylor Blau
2025-01-17 22:03 ` [PATCH v3 3/8] csum-file.c: extract algop from hashfile_checksum_valid() Taylor Blau
2025-01-17 22:03 ` [PATCH v3 4/8] hash.h: introduce `unsafe_hash_algo()` Taylor Blau
2025-01-17 22:03 ` [PATCH v3 5/8] csum-file.c: use unsafe_hash_algo() Taylor Blau
2025-01-17 22:03 ` [PATCH v3 6/8] t/helper/test-hash.c: " Taylor Blau
2025-01-17 22:03 ` [PATCH v3 7/8] csum-file: introduce hashfile_checkpoint_init() Taylor Blau
2025-01-17 22:03 ` [PATCH v3 8/8] hash.h: drop unsafe_ function variants Taylor Blau
2025-01-18 12:28 ` [PATCH v3 0/8] hash: introduce unsafe_hash_algo(), drop unsafe_ variants Jeff King
2025-01-18 12:43 ` Jeff King
2025-01-22 21:31 ` Junio C Hamano [this message]
2025-01-23 17:34 ` [PATCH v4 " Taylor Blau
2025-01-23 17:34 ` [PATCH v4 1/8] t/helper/test-tool: implement sha1-unsafe helper Taylor Blau
2025-01-23 17:34 ` [PATCH v4 2/8] csum-file: store the hash algorithm as a struct field Taylor Blau
2025-01-23 17:34 ` [PATCH v4 3/8] csum-file.c: extract algop from hashfile_checksum_valid() Taylor Blau
2025-01-23 17:34 ` [PATCH v4 4/8] hash.h: introduce `unsafe_hash_algo()` Taylor Blau
2025-01-23 17:34 ` [PATCH v4 5/8] csum-file.c: use unsafe_hash_algo() Taylor Blau
2025-01-23 17:34 ` [PATCH v4 6/8] t/helper/test-hash.c: " Taylor Blau
2025-01-23 17:34 ` [PATCH v4 7/8] csum-file: introduce hashfile_checkpoint_init() Taylor Blau
2025-01-23 17:34 ` [PATCH v4 8/8] hash.h: drop unsafe_ function variants Taylor Blau
2025-01-23 18:30 ` [PATCH v4 0/8] hash: introduce unsafe_hash_algo(), drop unsafe_ variants Junio C Hamano
2025-01-23 18:50 ` Jeff King
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