Subject: Re: git-2.13.0: log --date=format:%z not working

From: Junio C Hamano <[email-masked]>
Date: Fri, 02 Jun 2017 11:23:30 +0900

René Scharfe <[email-masked]> writes:

> Am 27.05.2017 um 23:46 schrieb Jeff King:
>> On Sat, May 27, 2017 at 06:57:08PM +0200, Ævar Arnfjörð Bjarmason wrote:
>> 
>>> There's another test which breaks if we just s/gmtime/localtime/g. As
>>> far as I can tell to make the non-local case work we'd need to do a
>>> whole dance where we set the TZ variable to e.g. UTC$offset, then call
>>> strftime(), then call it again. Maybe there's some way to just specify
>>> the tz offset, but I didn't find any in a quick skimming of time.h.
>> 
>> There isn't.
> Right.  We could handle %z internally, though.  %Z would be harder (left
> as an exercise for readers..).
>
> First we'd have to undo 0a0416a3 (strbuf_expand: convert "%%" to "%"),
> though, in order to give full control back to strbuf_expand callbacks.
>
> 2-pack patch:

I think the list concensus is that handling %z ourselves like this
one does is the best we can do portably.

Anybody wants to wrap this up into a patch with log message?

Thanks.

>
> --- >8 ---
>  builtin/cat-file.c         |  5 +++++
>  convert.c                  |  1 +
>  daemon.c                   |  3 +++
>  date.c                     |  2 +-
>  ll-merge.c                 |  5 +++--
>  pretty.c                   |  3 +++
>  strbuf.c                   | 39 ++++++++++++++++++++++++++++++---------
>  strbuf.h                   | 11 +++++------
>  t/t6006-rev-list-format.sh | 12 ++++++++++++
>  9 files changed, 63 insertions(+), 18 deletions(-)
>
> diff --git a/builtin/cat-file.c b/builtin/cat-file.c
> index 1890d7a639..9cf2e4291d 100644
> --- a/builtin/cat-file.c
> +++ b/builtin/cat-file.c
> @@ -252,6 +252,11 @@ static size_t expand_format(struct strbuf *sb, const char *start, void *data)
>  {
>  	const char *end;
>  
> +	if (*start == '%') {
> +		strbuf_addch(sb, '%');
> +		return 1;
> +	}
> +
>  	if (*start != '(')
>  		return 0;
>  	end = strchr(start + 1, ')');
> diff --git a/convert.c b/convert.c
> index 8d652bf27c..8336fff694 100644
> --- a/convert.c
> +++ b/convert.c
> @@ -399,6 +399,7 @@ static int filter_buffer_or_fd(int in, int out, void *data)
>  	struct strbuf path = STRBUF_INIT;
>  	struct strbuf_expand_dict_entry dict[] = {
>  		{ "f", NULL, },
> +		{ "%", "%" },
>  		{ NULL, NULL, },
>  	};
>  
> diff --git a/daemon.c b/daemon.c
> index ac7181a483..191fac2716 100644
> --- a/daemon.c
> +++ b/daemon.c
> @@ -148,6 +148,9 @@ static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
>  	case 'D':
>  		strbuf_addstr(sb, context->directory);
>  		return 1;
> +	case '%':
> +		strbuf_addch(sb, '%');
> +		return 1;
>  	}
>  	return 0;
>  }
> diff --git a/date.c b/date.c
> index 63fa99685e..d16a88eea5 100644
> --- a/date.c
> +++ b/date.c
> @@ -246,7 +246,7 @@ const char *show_date(timestamp_t time, int tz, const struct date_mode *mode)
>  			month_names[tm->tm_mon], tm->tm_year + 1900,
>  			tm->tm_hour, tm->tm_min, tm->tm_sec, tz);
>  	else if (mode->type == DATE_STRFTIME)
> -		strbuf_addftime(&timebuf, mode->strftime_fmt, tm);
> +		strbuf_addftime(&timebuf, mode->strftime_fmt, tm, tz);
>  	else
>  		strbuf_addf(&timebuf, "%.3s %.3s %d %02d:%02d:%02d %d%c%+05d",
>  				weekday_names[tm->tm_wday],
> diff --git a/ll-merge.c b/ll-merge.c
> index ac0d4a5d78..e6202c7397 100644
> --- a/ll-merge.c
> +++ b/ll-merge.c
> @@ -172,7 +172,7 @@ static int ll_ext_merge(const struct ll_merge_driver *fn,
>  {
>  	char temp[4][50];
>  	struct strbuf cmd = STRBUF_INIT;
> -	struct strbuf_expand_dict_entry dict[6];
> +	struct strbuf_expand_dict_entry dict[7];
>  	struct strbuf path_sq = STRBUF_INIT;
>  	const char *args[] = { NULL, NULL };
>  	int status, fd, i;
> @@ -185,7 +185,8 @@ static int ll_ext_merge(const struct ll_merge_driver *fn,
>  	dict[2].placeholder = "B"; dict[2].value = temp[2];
>  	dict[3].placeholder = "L"; dict[3].value = temp[3];
>  	dict[4].placeholder = "P"; dict[4].value = path_sq.buf;
> -	dict[5].placeholder = NULL; dict[5].value = NULL;
> +	dict[5].placeholder = "%"; dict[5].value = "%";
> +	dict[6].placeholder = NULL; dict[6].value = NULL;
>  
>  	if (fn->cmdline == NULL)
>  		die("custom merge driver %s lacks command line.", fn->name);
> diff --git a/pretty.c b/pretty.c
> index 587d48371b..56872bfa25 100644
> --- a/pretty.c
> +++ b/pretty.c
> @@ -1428,6 +1428,9 @@ static size_t format_commit_item(struct strbuf *sb, /* in UTF-8 */
>  	} magic = NO_MAGIC;
>  
>  	switch (placeholder[0]) {
> +	case '%':
> +		strbuf_addch(sb, '%');
> +		return 1;
>  	case '-':
>  		magic = DEL_LF_BEFORE_EMPTY;
>  		break;
> diff --git a/strbuf.c b/strbuf.c
> index 00457940cf..206dff6037 100644
> --- a/strbuf.c
> +++ b/strbuf.c
> @@ -309,12 +309,6 @@ void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn,
>  			break;
>  		format = percent + 1;
>  
> -		if (*format == '%') {
> -			strbuf_addch(sb, '%');
> -			format++;
> -			continue;
> -		}
> -
>  		consumed = fn(sb, format, context);
>  		if (consumed)
>  			format += consumed;
> @@ -785,7 +779,28 @@ char *xstrfmt(const char *fmt, ...)
>  	return ret;
>  }
>  
> -void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm)
> +struct date_format_context {
> +	int tz;
> +};
> +
> +static size_t expand_date_format(struct strbuf *sb, const char *placeholder,
> +				 void *ctx)
> +{
> +	struct date_format_context *c = ctx;
> +
> +	switch (placeholder[0]) {
> +	case '%':
> +		strbuf_addstr(sb, "%%");
> +		return 1;
> +	case 'z':
> +		strbuf_addf(sb, "%+05d", c->tz);
> +		return 1;
> +	}
> +	return 0;
> +}
> +
> +void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm,
> +		     int tz)
>  {
>  	size_t hint = 128;
>  	size_t len;
> @@ -794,7 +809,10 @@ void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm)
>  		return;
>  
>  	strbuf_grow(sb, hint);
> -	len = strftime(sb->buf + sb->len, sb->alloc - sb->len, fmt, tm);
> +	if (strstr(fmt, "%z"))
> +		len = 0;
> +	else
> +		len = strftime(sb->buf + sb->len, sb->alloc - sb->len, fmt, tm);
>  
>  	if (!len) {
>  		/*
> @@ -805,7 +823,10 @@ void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm)
>  		 * character before returning.
>  		 */
>  		struct strbuf munged_fmt = STRBUF_INIT;
> -		strbuf_addf(&munged_fmt, "%s ", fmt);
> +		struct date_format_context ctx;
> +		ctx.tz = tz;
> +		strbuf_expand(&munged_fmt, fmt, expand_date_format, &ctx);
> +		strbuf_addch(&munged_fmt, ' ');
>  		while (!len) {
>  			hint *= 2;
>  			strbuf_grow(sb, hint);
> diff --git a/strbuf.h b/strbuf.h
> index 80047b1bb7..fc4c796a2b 100644
> --- a/strbuf.h
> +++ b/strbuf.h
> @@ -281,10 +281,6 @@ extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);
>   * the length of the placeholder recognized and `strbuf_expand()` skips
>   * over it.
>   *
> - * The format `%%` is automatically expanded to a single `%` as a quoting
> - * mechanism; callers do not need to handle the `%` placeholder themselves,
> - * and the callback function will not be invoked for this placeholder.
> - *
>   * All other characters (non-percent and not skipped ones) are copied
>   * verbatim to the strbuf.  If the callback returned zero, meaning that the
>   * placeholder is unknown, then the percent sign is copied, too.
> @@ -339,9 +335,12 @@ __attribute__((format (printf,2,0)))
>  extern void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap);
>  
>  /**
> - * Add the time specified by `tm`, as formatted by `strftime`.
> + * Add the time specified by `tm` and `tz`, as formatted by `strftime`.
> + * The time zone offset is specified like hhmm, so e.g. -600 means six
> + * hours west of Greenwich.
>   */
> -extern void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm);
> +extern void strbuf_addftime(struct strbuf *sb, const char *fmt,
> +			    const struct tm *tm, int tz);
>  
>  /**
>   * Read a given size of data from a FILE* pointer to the buffer.
> diff --git a/t/t6006-rev-list-format.sh b/t/t6006-rev-list-format.sh
> index a1dcdb81d7..dc0bed8d90 100755
> --- a/t/t6006-rev-list-format.sh
> +++ b/t/t6006-rev-list-format.sh
> @@ -483,4 +483,16 @@ test_expect_success 'unused %G placeholders are passed through' '
>  	test_cmp expect actual
>  '
>  
> +test_expect_success 'date format "%F %T %z" is the same as iso' '
> +	git log -1 --format="%ad" --date=iso >expect &&
> +	git log -1 --format="%ad" --date="format:%F %T %z" >actual &&
> +	test_cmp expect actual
> +'
> +
> +test_expect_success 'date format "%%z" expands to percent zed' '
> +	echo "%z" >expect &&
> +	git log -1 --format="%ad" --date="format:%%z" >actual &&
> +	test_cmp expect actual
> +'
> +
>  test_done