Subject: Re: [PATCH] date: make "iso-strict" conforming for the UTC timezone

From: Junio C Hamano <[email-masked]>
Date: Wed, 13 Mar 2024 11:30:42 -0700

"Beat Bolli" <[email-masked]> writes:

> ISO 8601-1:2020-12 specifies that a zero timezone offset must be denoted
> with a "Z" suffix instead of the numeric "+00:00". Add the correponding
> special case to show_date() and a new test.

Hmph, would this break existing scripts that expects the current
behaviour, and if it does, is it safe for us to blame the script
authors for not following the standard?

Assuming that we do not need to worry about them, the patch itself
looks perfectly reasonable to me.

Thanks.

> Reported-by: Michael Osipov <[email-masked]>
> Link: https://lore.kernel.org/git/[email-masked]/
> Signed-off-by: Beat Bolli <[email-masked]>
> ---
>  date.c          | 14 +++++++++-----
>  t/t0006-date.sh |  1 +
>  2 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/date.c b/date.c
> index 619ada5b2044..44cf2221d81f 100644
> --- a/date.c
> +++ b/date.c
> @@ -342,14 +342,18 @@ const char *show_date(timestamp_t time, int tz, const struct date_mode *mode)
>  				tm->tm_hour, tm->tm_min, tm->tm_sec,
>  				tz);
>  	else if (mode->type == DATE_ISO8601_STRICT) {
> -		char sign = (tz >= 0) ? '+' : '-';
> -		tz = abs(tz);
> -		strbuf_addf(&timebuf, "%04d-%02d-%02dT%02d:%02d:%02d%c%02d:%02d",
> +		strbuf_addf(&timebuf, "%04d-%02d-%02dT%02d:%02d:%02d",
>  				tm->tm_year + 1900,
>  				tm->tm_mon + 1,
>  				tm->tm_mday,
> -				tm->tm_hour, tm->tm_min, tm->tm_sec,
> -				sign, tz / 100, tz % 100);
> +				tm->tm_hour, tm->tm_min, tm->tm_sec);
> +		if (tz == 0) {
> +			strbuf_addch(&timebuf, 'Z');
> +		} else {
> +			strbuf_addch(&timebuf, tz >= 0 ? '+' : '-');
> +			tz = abs(tz);
> +			strbuf_addf(&timebuf, "%02d:%02d", tz / 100, tz % 100);
> +		}
>  	} else if (mode->type == DATE_RFC2822)
>  		strbuf_addf(&timebuf, "%.3s, %d %.3s %d %02d:%02d:%02d %+05d",
>  			weekday_names[tm->tm_wday], tm->tm_mday,
> diff --git a/t/t0006-date.sh b/t/t0006-date.sh
> index e18b1602864e..1d228a981ee9 100755
> --- a/t/t0006-date.sh
> +++ b/t/t0006-date.sh
> @@ -46,6 +46,7 @@ check_show () {
>  TIME='1466000000 +0200'
>  check_show iso8601 "$TIME" '2016-06-15 16:13:20 +0200'
>  check_show iso8601-strict "$TIME" '2016-06-15T16:13:20+02:00'
> +check_show iso8601-strict "$(echo "$TIME" | sed 's/+0200$/+0000/')" '2016-06-15T14:13:20Z'
>  check_show rfc2822 "$TIME" 'Wed, 15 Jun 2016 16:13:20 +0200'
>  check_show short "$TIME" '2016-06-15'
>  check_show default "$TIME" 'Wed Jun 15 16:13:20 2016 +0200'