From: Linus Arver <linusa@google.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Linus Arver via GitGitGadget <gitgitgadget@gmail.com>,
git@vger.kernel.org, Christian Couder <chriscool@tuxfamily.org>,
Phillip Wood <phillip.wood123@gmail.com>
Subject: Re: [PATCH v2 5/6] trailer: rename *_DEFAULT enums to *_UNSPECIFIED
Date: Fri, 22 Sep 2023 11:23:16 -0700 [thread overview]
Message-ID: <owly8r8yt6cr.fsf@fine.c.googlers.com> (raw)
In-Reply-To: <xmqq1qf1la0q.fsf@gitster.g>
Junio C Hamano <gitster@pobox.com> writes:
> Linus Arver <linusa@google.com> writes:
>
>>> It gets tempting to initialize a variable to the default and arrange
>>> the rest of the system so that the variable set to the default
>>> triggers the default activity. Such an obvious solution however
>>> cannot be used when (1) being left unspecified to use the default
>>> value and (2) explicitly set by the user to a value that happens to
>>> be the same as the default have to behave differently. I am not
>>> sure if that applies to the trailers system, though.
>>>
>>> Thanks.
>>
>> I get the feeling that you wrote the "Such an obvious ... differently"
>> sentence after writing the last sentence in that paragraph, because when
>> you say
>>
>> I am not
>> sure if that applies to the trailers system, though.
>>
>> I read the "that" (emphasis added) in there as referring to the solution
>> described in the first sentence, and not the conditions (1) and (2) you
>> enumerated. IOW, you are OK with this patch.
>
> "that" refers to "the reason not to use such an obvious solution".
> I do not know if trailer subsystem wants to treat "left unspecified"
> and "set to the value that happens to be the same as the default" in
> a different way. If it does want to do so, then I do not see a
> strong reason not to use the "obvious solution".
Currently we set the defaults (these take effect absent any
configuration or CLI options) in trailer.c like this:
static void ensure_configured(void)
{
if (configured)
return;
/* Default config must be setup first */
default_conf_info.where = WHERE_END;
default_conf_info.if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
default_conf_info.if_missing = MISSING_ADD;
git_config(git_trailer_default_config, NULL);
git_config(git_trailer_config, NULL);
configured = 1;
}
So technically we already sort of do the "obvious solution". And then
these get overriden by configuration (if any), and finally any CLI
options that are passed in (e.g., "--where after"). The reason why I
prefer the *_UNSPECIFIED style in this patch for these enums though is
because of this (and other similar functions) in trailer.c:
int trailer_set_where(enum trailer_where *item, const char *value)
{
if (!value)
*item = WHERE_DEFAULT;
else if (!strcasecmp("after", value))
*item = WHERE_AFTER;
else if (!strcasecmp("before", value))
*item = WHERE_BEFORE;
else if (!strcasecmp("end", value))
*item = WHERE_END;
else if (!strcasecmp("start", value))
*item = WHERE_START;
else
return -1;
return 0;
}
and this function is used as a callback to the "--where" flag, such that
the WHERE_DEFAULT gets chosen if "--no-where" is where. I prefer the
WHERE_UNSPECIFIED as in this patch because the WHERE_DEFAULT is
ambiguous on its own (i.e., WHERE_DEFAULT could mean that we either use
the default value WHERE_END in default_conf_info, or it could mean that
we fall back to the configuration variables (where it could be something
else)).
next prev parent reply other threads:[~2023-09-22 18:23 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
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 [this message]
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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