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From: Junio C Hamano <gitster@pobox.com>
To: Derrick Stolee <stolee@gmail.com>
Cc: Taylor Blau <me@ttaylorr.com>,
	git@vger.kernel.org, peff@peff.net, jrnieder@gmail.com
Subject: Re: [PATCH 00/20] pack-revindex: prepare for on-disk reverse index
Date: Mon, 11 Jan 2021 10:40:44 -0800	[thread overview]
Message-ID: <xmqqlfcz8ggj.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <7e56e831-c6d6-3454-94c5-b8e888497568@gmail.com> (Derrick Stolee's message of "Mon, 11 Jan 2021 12:15:58 -0500")

Derrick Stolee <stolee@gmail.com> writes:

> Well, I found 782 instances of ") < 0)" in the codebase, and my initial
> scan of these shows they are doing exactly what you are asking. So as
> far as code style goes, there is plenty of precedent.
>
> The thing that makes me react to this is that it _looks_ like an extra
> comparison. However, I'm sure the assembly instructions have the same
> performance characteristics between "!= 0" and "< 0".

I'd prefer to keep it that way for the human cost's point of view.

Perhaps it could be subjective but

	if (func_that_signals_error_with_return_value() < 0)

is immediately recognizable as checking for an error to folks who
were trained to write C in POSIX environment, as "on error, return
negative" is a convention that they are familiar with.  At least to
me, your "if (func_that_signals_error_with_return_value())" looks
unnatural and makes me look at the function to see what its return
value means.

If there are helper functions that use "non-zero is an error and
zero is success" convention, we should look at them to see why they
do not do the usual "a negative is an error and a non-negative is
success".  And if the *only* reason they do so is because their
normal return do not have to give more than one kind of "success",
we should see if we can fix them to follow the usual "a negative is
an error" convention, I would think.

Thanks.

  parent reply	other threads:[~2021-01-11 18:42 UTC|newest]

Thread overview: 121+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-08 18:16 [PATCH 00/20] pack-revindex: prepare for on-disk reverse index Taylor Blau
2021-01-08 18:16 ` [PATCH 01/20] pack-revindex: introduce a new API Taylor Blau
2021-01-12  8:41   ` Jeff King
2021-01-12  9:41     ` Jeff King
2021-01-12 16:27     ` Taylor Blau
2021-01-13  8:06   ` Junio C Hamano
2021-01-13  8:54     ` Junio C Hamano
2021-01-13 13:17     ` Jeff King
2021-01-13 16:23     ` Taylor Blau
2021-01-08 18:16 ` [PATCH 02/20] write_reuse_object(): convert to new revindex API Taylor Blau
2021-01-12  8:47   ` Jeff King
2021-01-12 16:31     ` Taylor Blau
2021-01-13 13:02       ` Jeff King
2021-01-08 18:16 ` [PATCH 03/20] write_reused_pack_one(): " Taylor Blau
2021-01-12  8:50   ` Jeff King
2021-01-12 16:34     ` Taylor Blau
2021-01-08 18:16 ` [PATCH 04/20] write_reused_pack_verbatim(): " Taylor Blau
2021-01-12  8:50   ` Jeff King
2021-01-08 18:17 ` [PATCH 05/20] check_object(): " Taylor Blau
2021-01-11 11:43   ` Derrick Stolee
2021-01-11 16:15     ` Taylor Blau
2021-01-12  8:54       ` Jeff King
2021-01-12  8:51   ` Jeff King
2021-01-08 18:17 ` [PATCH 06/20] bitmap_position_packfile(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 07/20] show_objects_for_type(): " Taylor Blau
2021-01-12  8:57   ` Jeff King
2021-01-12 16:35     ` Taylor Blau
2021-01-08 18:17 ` [PATCH 08/20] get_size_by_pos(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 09/20] try_partial_reuse(): " Taylor Blau
2021-01-12  9:06   ` Jeff King
2021-01-12 16:47     ` Taylor Blau
2021-01-08 18:17 ` [PATCH 10/20] rebuild_existing_bitmaps(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 11/20] get_delta_base_oid(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 12/20] retry_bad_packed_offset(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 13/20] packed_object_info(): " Taylor Blau
2021-01-12  9:11   ` Jeff King
2021-01-12 16:51     ` Taylor Blau
2021-01-08 18:17 ` [PATCH 14/20] unpack_entry(): " Taylor Blau
2021-01-12  9:22   ` Jeff King
2021-01-12 16:56     ` Taylor Blau
2021-01-08 18:17 ` [PATCH 15/20] for_each_object_in_pack(): " Taylor Blau
2021-01-08 18:17 ` [PATCH 16/20] builtin/gc.c: guess the size of the revindex Taylor Blau
2021-01-11 11:52   ` Derrick Stolee
2021-01-11 16:23     ` Taylor Blau
2021-01-11 17:09       ` Derrick Stolee
2021-01-12  9:28         ` Jeff King
2021-01-08 18:17 ` [PATCH 17/20] pack-revindex: remove unused 'find_pack_revindex()' Taylor Blau
2021-01-08 18:17 ` [PATCH 18/20] pack-revindex: remove unused 'find_revindex_position()' Taylor Blau
2021-01-11 11:57   ` Derrick Stolee
2021-01-11 16:27     ` Taylor Blau
2021-01-11 17:11       ` Derrick Stolee
2021-01-12  9:32   ` Jeff King
2021-01-12 16:59     ` Taylor Blau
2021-01-13 13:05       ` Jeff King
2021-01-08 18:18 ` [PATCH 19/20] pack-revindex: hide the definition of 'revindex_entry' Taylor Blau
2021-01-11 11:57   ` Derrick Stolee
2021-01-12  9:34   ` Jeff King
2021-01-08 18:18 ` [PATCH 20/20] pack-revindex.c: avoid direct revindex access in 'offset_to_pack_pos()' Taylor Blau
2021-01-12  9:37   ` Jeff King
2021-01-12 17:02     ` Taylor Blau
2021-01-11 12:07 ` [PATCH 00/20] pack-revindex: prepare for on-disk reverse index Derrick Stolee
2021-01-11 16:30   ` Taylor Blau
2021-01-11 17:15     ` Derrick Stolee
2021-01-11 17:29       ` Taylor Blau
2021-01-11 18:40       ` Junio C Hamano [this message]
2021-01-12  9:45 ` Jeff King
2021-01-12 17:07   ` Taylor Blau
2021-01-13  0:23 ` Junio C Hamano
2021-01-13  0:52   ` Taylor Blau
2021-01-13  2:15     ` Junio C Hamano
2021-01-13  3:23       ` Taylor Blau
2021-01-13  8:21         ` Junio C Hamano
2021-01-13 13:13           ` Jeff King
2021-01-13 15:34             ` Taylor Blau
2021-01-13 20:06               ` Junio C Hamano
2021-01-13 20:13                 ` Taylor Blau
2021-01-13 20:22                 ` Jeff King
2021-01-13 22:23 ` [PATCH v2 " Taylor Blau
2021-01-13 22:23   ` [PATCH v2 01/20] pack-revindex: introduce a new API Taylor Blau
2021-01-14  6:46     ` Junio C Hamano
2021-01-14 12:00       ` Derrick Stolee
2021-01-14 17:06       ` Taylor Blau
2021-01-14 19:19         ` Jeff King
2021-01-14 20:47           ` Junio C Hamano
2021-01-13 22:23   ` [PATCH v2 02/20] write_reuse_object(): convert to new revindex API Taylor Blau
2021-01-13 22:23   ` [PATCH v2 03/20] write_reused_pack_one(): " Taylor Blau
2021-01-13 22:23   ` [PATCH v2 04/20] write_reused_pack_verbatim(): " Taylor Blau
2021-01-13 22:23   ` [PATCH v2 05/20] check_object(): " Taylor Blau
2021-01-13 22:23   ` [PATCH v2 06/20] bitmap_position_packfile(): " Taylor Blau
2021-01-13 22:23   ` [PATCH v2 07/20] show_objects_for_type(): " Taylor Blau
2021-01-13 22:24   ` [PATCH v2 08/20] get_size_by_pos(): " Taylor Blau
2021-01-13 22:24   ` [PATCH v2 09/20] try_partial_reuse(): " Taylor Blau
2021-01-13 22:24   ` [PATCH v2 10/20] rebuild_existing_bitmaps(): " Taylor Blau
2021-01-13 22:24   ` [PATCH v2 11/20] get_delta_base_oid(): " Taylor Blau
2021-01-13 22:24   ` [PATCH v2 12/20] retry_bad_packed_offset(): " Taylor Blau
2021-01-13 22:24   ` [PATCH v2 13/20] packed_object_info(): " Taylor Blau
2021-01-13 22:24   ` [PATCH v2 14/20] unpack_entry(): " Taylor Blau
2021-01-13 22:24   ` [PATCH v2 15/20] for_each_object_in_pack(): " Taylor Blau
2021-01-14  6:43     ` Junio C Hamano
2021-01-14 17:00       ` Taylor Blau
2021-01-14 19:33       ` Jeff King
2021-01-14 20:11         ` Jeff King
2021-01-14 20:15           ` Taylor Blau
2021-01-15  2:22             ` Junio C Hamano
2021-01-15  2:29               ` Taylor Blau
2021-01-14 20:51         ` Junio C Hamano
2021-01-13 22:24   ` [PATCH v2 16/20] builtin/gc.c: guess the size of the revindex Taylor Blau
2021-01-14  6:33     ` Junio C Hamano
2021-01-14 16:53       ` Taylor Blau
2021-01-14 19:43         ` Jeff King
2021-01-13 22:24   ` [PATCH v2 17/20] pack-revindex: remove unused 'find_pack_revindex()' Taylor Blau
2021-01-13 22:25   ` [PATCH v2 18/20] pack-revindex: remove unused 'find_revindex_position()' Taylor Blau
2021-01-14  6:42     ` Junio C Hamano
2021-01-13 22:25   ` [PATCH v2 19/20] pack-revindex: hide the definition of 'revindex_entry' Taylor Blau
2021-01-13 22:25   ` [PATCH v2 20/20] pack-revindex.c: avoid direct revindex access in 'offset_to_pack_pos()' Taylor Blau
2021-01-14  6:42     ` Junio C Hamano
2021-01-14 16:56       ` Taylor Blau
2021-01-14 19:51   ` [PATCH v2 00/20] pack-revindex: prepare for on-disk reverse index Jeff King
2021-01-14 20:53     ` Junio C Hamano
2021-01-15  9:32       ` Jeff King
2021-01-15  9:33         ` Jeff King

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