Re: [PATCH v2] format-patch: allow a non-integral version numbers

> From: ZheNing Hu <adlternative@gmail.com>
> 
> Usually we can only use `format-patch -v<n>` to generate integral
> version numbers patches, but sometimes a same fixup should be
> laveled as a non-integral versions like `v1.1`,so teach format-patch

> allow a non-integral versions may be helpful to send those patches.
> 
> Since the original `format-patch` logic, if we specify a version `-v<n>`
> and commbine with `--interdiff` or `--rangediff`, the patch will output
> "Interdiff again v<n-1>:" or "Range-diff again v<n-1>:`, but this does
> not meet the requirements of our fractional version numbers, so provide
> `format patch` a new option `--previous-count=<n>`, the patch can output
> user-specified previous version number. If the user use a integral version
> number `-v<n>`, ensure that the output in the patch is still `v<n-1>`.
> (let `--previous-count` become invalid.)

> diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
> index 3e49bf221087..f10fa6527f5f 100644
> --- a/Documentation/git-format-patch.txt
> +++ b/Documentation/git-format-patch.txt
> @@ -22,6 +22,7 @@ SYNOPSIS
>  		   [--cover-from-description=<mode>]
>  		   [--rfc] [--subject-prefix=<subject prefix>]
>  		   [(--reroll-count|-v) <n>]
> +		   [--previous-count=<n>]
>  		   [--to=<email>] [--cc=<email>]
>  		   [--[no-]cover-letter] [--quiet]
>  		   [--[no-]encode-email-headers]
> @@ -221,6 +222,15 @@ populated with placeholder text.
>  	`--subject-prefix` option) has ` v<n>` appended to it.  E.g.
>  	`--reroll-count=4` may produce `v4-0001-add-makefile.patch`
>  	file that has "Subject: [PATCH v4 1/20] Add makefile" in it.
> +	now can support non-integrated version number like `-v1.1`.
> +
> +--previous-count=<n>::
> +	Under the premise that we have used `--reroll-count=<n>`,
> +	we can use `--previous-count=<n>` to specify the previous
> +	version number. E.g. When we use the `--range-diff` or
> +	`--interdiff` option and combine with `-v2.3 --previous-count=2.2`,
> +	"Interdiff against v2.2:" or "Range-diff against v2.2:"
> +	will be output in the patch.
>  
>  --to=<email>::
>  	Add a `To:` header to the email headers. This is in addition
> diff --git a/builtin/log.c b/builtin/log.c
> index f67b67d80ed1..95c95eab5393 100644
> --- a/builtin/log.c
> +++ b/builtin/log.c
> @@ -1662,13 +1662,15 @@ static void print_bases(struct base_tree_info *bases, FILE *file)
>  	oidclr(&bases->base_commit);
>  }
>  
> -static const char *diff_title(struct strbuf *sb, int reroll_count,
> -		       const char *generic, const char *rerolled)
> +static const char *diff_title(struct strbuf *sb, const char *reroll_count, int reroll_count_is_integer,
> +			const char*previous_count, const char *generic, const char *rerolled)
>  {
> -	if (reroll_count <= 0)
> +	if (!reroll_count || (!reroll_count_is_integer && !previous_count))
>  		strbuf_addstr(sb, generic);
> -	else /* RFC may be v0, so allow -v1 to diff against v0 */
> -		strbuf_addf(sb, rerolled, reroll_count - 1);
> +	else if (reroll_count_is_integer)/* RFC may be v0, so allow -v1 to diff against v0 */
> +		strbuf_addf(sb, rerolled, atoi(reroll_count) - 1);
> +	else if (previous_count)
> +		strbuf_addf(sb, rerolled, previous_count);
>  	return sb->buf;
>  }

> @@ -1717,7 +1719,9 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
>  	struct strbuf buf = STRBUF_INIT;
>  	int use_patch_format = 0;
>  	int quiet = 0;
> -	int reroll_count = -1;
> +	int reroll_count_is_integer = 0;
> +	const char *reroll_count = NULL;
> +	const char *previous_count = NULL;

>  	char *cover_from_description_arg = NULL;
>  	char *branch_name = NULL;
>  	char *base_commit = NULL;
> @@ -1751,8 +1755,10 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
>  			    N_("use <sfx> instead of '.patch'")),
>  		OPT_INTEGER(0, "start-number", &start_number,
>  			    N_("start numbering patches at <n> instead of 1")),
> -		OPT_INTEGER('v', "reroll-count", &reroll_count,
> -			    N_("mark the series as Nth re-roll")),
> +		OPT_STRING('v', "reroll-count", &reroll_count, N_("reroll-count"),
> +			    N_("mark the series as specified version re-roll")),
> +		OPT_STRING(0, "previous-count", &previous_count, N_("previous-count"),
> +			    N_("specified as the last version while we use --reroll-count")),
>  		OPT_INTEGER(0, "filename-max-length", &fmt_patch_name_max,
>  			    N_("max length of output filename")),
>  		OPT_CALLBACK_F(0, "rfc", &rev, NULL,
> @@ -1861,10 +1867,20 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
>  
>  	if (cover_from_description_arg)
>  		cover_from_description_mode = parse_cover_from_description(cover_from_description_arg);
> -
> -	if (0 < reroll_count) {
> +	if (previous_count && !reroll_count)
> +		usage(_("previous-count can only used when reroll-count is used"));
> +	if (reroll_count) {
>  		struct strbuf sprefix = STRBUF_INIT;
> -		strbuf_addf(&sprefix, "%s v%d",
> +		char ch;
> +		size_t i = 0 , reroll_count_len = strlen(reroll_count);
> +
> +		for (; i != reroll_count_len; i++) {
> +			ch = reroll_count[i];
> +			if(!isdigit(ch))
> +				break;
> +		}
> +		reroll_count_is_integer = i == reroll_count_len ? 1 : 0;
> +		strbuf_addf(&sprefix, "%s v%s",
>  			    rev.subject_prefix, reroll_count);
>  		rev.reroll_count = reroll_count;
>  		rev.subject_prefix = strbuf_detach(&sprefix, NULL);