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From: Linus Arver <linusa@google.com>
To: Glen Choo <chooglen@google.com>,
	Linus Arver via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org
Subject: Re: [PATCH 4/5] trailer: teach find_patch_start about --no-divider
Date: Thu, 10 Aug 2023 18:25:46 -0700	[thread overview]
Message-ID: <owlyjzu2fjz9.fsf@fine.c.googlers.com> (raw)
In-Reply-To: <kl6ly1im8ma5.fsf@chooglen-macbookpro.roam.corp.google.com>

Glen Choo <chooglen@google.com> writes:

> "Linus Arver via GitGitGadget" <gitgitgadget@gmail.com> writes:
>> @@ -812,14 +812,14 @@ static ssize_t last_line(const char *buf, size_t len)
>>   * Return the position of the start of the patch or the length of str if there
>>   * is no patch in the message.
>>   */
>> -static size_t find_patch_start(const char *str)
>> +static size_t find_patch_start(const char *str, int no_divider)
>>  {
>>  	const char *s;
>>  
>>  	for (s = str; *s; s = next_line(s)) {
>>  		const char *v;
>>  
>> -		if (skip_prefix(s, "---", &v) && isspace(*v))
>> +		if (!no_divider && skip_prefix(s, "---", &v) && isspace(*v))
>>  			return s - str;
>>  	}
>
> Assuming we wanted to make this unit-testable anyway, could we just move
> the strlen() call into this function?

I don't see why we should preserve the if-statement and associated
strlen() call if we can just get rid of it.

> [...] I
> don't find this easier to understand. Now the reader needs to read the
> code to see "if no_divider is given, noop until the end of the string,
> at which point str will point to the end, and s - str will give us the
> length of str", as opposed to "there are no dividers, so just return
> strlen(str)".

The main idea behind this patch is to make find_patch_start() return the
correct answer. Currently it does not in all cases (whether --no-divider
is provided), and so the caller has to calculate the
start of the patch with strlen manually. By moving the --no-divider flag
into this function, we force all callers to consider this important
option.

For additional context we recently had to fix a bug where we weren't
passing in this flag to the interpret-trailers builtin. See be3d654343
(commit: pass --no-divider to interpret-trailers, 2023-06-17). There we
acknowledged that some callers forgot to pass in --no-divider to
interpret-trailers (such as the caller that was fixed up in that
commit).

I mention the above example because although it's not the exact same
thing as here, I think the scenario of "sometimes callers can forget
about --no-divider" is an important one to prevent wherever possible.
That's why I like this patch (in addition to the reasons cited in the
commit message).

  reply	other threads:[~2023-08-11  1:25 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-05  5:04 [PATCH 0/5] Trailer readability cleanups Linus Arver via GitGitGadget
2023-08-05  5:04 ` [PATCH 1/5] trailer: separate public from internal portion of trailer_iterator Linus Arver via GitGitGadget
2023-08-07 21:16   ` Glen Choo
2023-08-08 12:19     ` Phillip Wood
2023-08-10 23:15       ` Linus Arver
2023-08-10 22:50     ` Linus Arver
2023-08-05  5:04 ` [PATCH 2/5] trailer: split process_input_file into separate pieces Linus Arver via GitGitGadget
2023-08-07 22:39   ` Glen Choo
2023-08-11  0:41     ` Linus Arver
2023-08-05  5:04 ` [PATCH 3/5] trailer: split process_command_line_args into separate functions Linus Arver via GitGitGadget
2023-08-07 22:51   ` Glen Choo
2023-08-11  0:59     ` Linus Arver
2023-08-11  1:02       ` Linus Arver
2023-08-11 21:11       ` Glen Choo
2023-08-05  5:04 ` [PATCH 4/5] trailer: teach find_patch_start about --no-divider Linus Arver via GitGitGadget
2023-08-07 23:28   ` Glen Choo
2023-08-11  1:25     ` Linus Arver [this message]
2023-08-11 20:51       ` Glen Choo
2023-08-05  5:04 ` [PATCH 5/5] trailer: rename *_DEFAULT enums to *_UNSPECIFIED Linus Arver via GitGitGadget
2023-08-07 23:45   ` Glen Choo
2023-08-11 18:00     ` Linus Arver
2023-09-09  6:16 ` [PATCH v2 0/6] Trailer readability cleanups Linus Arver via GitGitGadget
2023-09-09  6:16   ` [PATCH v2 1/6] trailer: separate public from internal portion of trailer_iterator Linus Arver via GitGitGadget
2023-09-11 17:10     ` Junio C Hamano
2023-09-09  6:16   ` [PATCH v2 2/6] trailer: split process_input_file into separate pieces Linus Arver via GitGitGadget
2023-09-11 17:10     ` Junio C Hamano
2023-09-09  6:16   ` [PATCH v2 3/6] trailer: split process_command_line_args into separate functions Linus Arver via GitGitGadget
2023-09-09  6:16   ` [PATCH v2 4/6] trailer: teach find_patch_start about --no-divider Linus Arver via GitGitGadget
2023-09-11 17:25     ` Junio C Hamano
2023-09-14  2:19       ` Linus Arver
2023-09-14  3:12         ` Junio C Hamano
2023-09-14  5:31           ` Linus Arver
2023-09-09  6:16   ` [PATCH v2 5/6] trailer: rename *_DEFAULT enums to *_UNSPECIFIED Linus Arver via GitGitGadget
2023-09-11 18:54     ` Junio C Hamano
2023-09-14  2:41       ` Linus Arver
2023-09-14  3:16         ` Junio C Hamano
2023-09-22 18:23           ` Linus Arver
2023-09-22 19:48             ` Junio C Hamano
2023-09-26  5:30               ` Linus Arver
2023-09-09  6:16   ` [PATCH v2 6/6] trailer: use offsets for trailer_start/trailer_end Linus Arver via GitGitGadget
2023-09-11 19:01     ` Junio C Hamano
2023-09-14  1:21       ` Linus Arver
2023-09-14  3:18         ` Linus Arver
2023-09-22 19:50   ` [PATCH v3 0/9] Trailer readability cleanups Linus Arver via GitGitGadget
2023-09-22 19:50     ` [PATCH v3 1/9] trailer: separate public from internal portion of trailer_iterator Linus Arver via GitGitGadget
2023-09-22 19:50     ` [PATCH v3 2/9] trailer: split process_input_file into separate pieces Linus Arver via GitGitGadget
2023-09-22 19:50     ` [PATCH v3 3/9] trailer: split process_command_line_args into separate functions Linus Arver via GitGitGadget
2023-09-22 19:50     ` [PATCH v3 4/9] trailer: rename *_DEFAULT enums to *_UNSPECIFIED Linus Arver via GitGitGadget
2023-09-22 19:50     ` [PATCH v3 5/9] commit: ignore_non_trailer computes number of bytes to ignore Linus Arver via GitGitGadget
2023-09-22 19:50     ` [PATCH v3 6/9] trailer: find the end of the log message Linus Arver via GitGitGadget
2023-09-22 19:50     ` [PATCH v3 7/9] trailer: use offsets for trailer_start/trailer_end Linus Arver via GitGitGadget
2023-09-22 19:50     ` [PATCH v3 8/9] trailer: only use trailer_block_* variables if trailers were found Linus Arver via GitGitGadget
2023-09-22 19:50     ` [PATCH v3 9/9] trailer: make stack variable names match field names Linus Arver via GitGitGadget
2023-09-22 22:47     ` [PATCH v3 0/9] Trailer readability cleanups Junio C Hamano
2023-09-22 23:13       ` Linus Arver
2023-09-23  0:48         ` Junio C Hamano
2023-09-26  5:40           ` Linus Arver
2023-09-26  6:22     ` [PATCH v4 0/4] " Linus Arver via GitGitGadget
2023-09-26  6:22       ` [PATCH v4 1/4] commit: ignore_non_trailer computes number of bytes to ignore Linus Arver via GitGitGadget
2023-09-26  6:22       ` [PATCH v4 2/4] trailer: find the end of the log message Linus Arver via GitGitGadget
2023-09-28 23:16         ` Jonathan Tan
2023-10-20  0:24           ` Linus Arver
2023-10-20  0:36             ` Junio C Hamano
2023-09-26  6:22       ` [PATCH v4 3/4] trailer: use offsets for trailer_start/trailer_end Linus Arver via GitGitGadget
2023-09-26  6:22       ` [PATCH v4 4/4] trailer: only use trailer_block_* variables if trailers were found Linus Arver via GitGitGadget
2023-10-20 19:01       ` [PATCH v5 0/3] Trailer readability cleanups Linus Arver via GitGitGadget
2023-10-20 19:01         ` [PATCH v5 1/3] commit: ignore_non_trailer computes number of bytes to ignore Linus Arver via GitGitGadget
2023-10-20 19:01         ` [PATCH v5 2/3] trailer: find the end of the log message Linus Arver via GitGitGadget
2023-10-20 21:29           ` Junio C Hamano
2023-12-29  6:42             ` Linus Arver
2023-12-29 21:03               ` Linus Arver
2023-10-20 19:01         ` [PATCH v5 3/3] trailer: use offsets for trailer_start/trailer_end Linus Arver via GitGitGadget

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