Re: [PATCH] rev-list: clarify git-log default date format

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Feb 1, 2023, 22:28 UTC
Message-ID: <230201.864js5q9sv.gmgdl@evledraar.gmail.com>
In-Reply-To: <xmqq5ycl1c6h.fsf@gitster.g>

On Wed, Feb 01 2023, Junio C Hamano wrote:

Show 53 quoted lines

> Rafael Dulfer <rafael@dulfer.be> writes:
>
>> From: Rafael Dulfer <rafael.dulfer@gmail.com>
>>
>> Currently, the documentation is slightly incomplete, not explaining
>> all the differences the default format has with rfc2822. Leading to
>> confusion for people trying to parse the date format outputted by
>> git log
>>
>> This patch adds 2 more exceptions when compared to rfc2822. Also
>> adds an example of what the format looks like (I originally wanted
>> to specify this in strftime notation, but because of the way
>> day-of-month is formatted this is impossible)
>
> Overly long lines.
>
>>
>> Signed-off-by: Rafael Dulfer <rafael.dulfer@gmail.com>
>> ---
>>  Documentation/rev-list-options.txt | 10 ++++++++--
>>  1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
>> index ff68e48406..8bc8475f3e 100644
>> --- a/Documentation/rev-list-options.txt
>> +++ b/Documentation/rev-list-options.txt
>> @@ -1103,9 +1103,15 @@ format placeholders. When using `-local`, the correct syntax is
>>  `--date=default` is the default format, and is similar to
>>  `--date=rfc2822`, with a few exceptions:
>>  --
>> -	- there is no comma after the day-of-week
>> +	- There is no comma after the day-of-week
>>  
>> -	- the time zone is omitted when the local time zone is used
>> +	- The time zone is omitted when the local time zone is used
>> +
>> +	- Day-of-month and month are switched around
>> +
>> +	- Time-of-day and the year are switched around
>> +
>> +As a result, the format looks as follows: `Thu Jan 1 00:00:00 1970 +0000` with `+0000` being omitted when the local time zone is used.
>
> All of the above may technically be correct, but I wonder if it
> makes it easier to follow to simply stop saying "is similar to".
> That is
>
>     The default format `--date=default` shows a single line with
>     three-letter day of the week, three-letter month, day-of-month,
>     hour-minute-second in the "HH:MM:SS" format, followed by 4-digit
>     year, plus timezone information unless the local time zone is
>     used (e.g. "Thu Jan 1 00:00:00 1970 +0000").
>
> or something like that.

I think that following such a description in prose is still more
confusing than just showing an example. E.g. we could say:
	
	Assuming a user in timezone +0200 (Central Europe) values of
	these `--date` argument would produce:
	
	|---------------+--------------------------------|
	| rfc2822       | Thu, 7 Apr 2005 15:13:13 -0700 |
	| rfc2822-local | Fri, 8 Apr 2005 00:13:13 +0200 |
	| default       | Thu Apr 7 15:13:13 2005 -0700  |
	| default-local | Fri Apr 8 00:13:13 2005        |
	|---------------+--------------------------------|
	
In particular your example says "unless the local time zone is used",
but then shows an example that's 'default', not 'default-local'.