Subject: Re: [PATCH v4 2/2] format-patch: "--rfc=-(WIP)" appends to produce [PATCH (WIP)]

From: Phillip Wood <[email-masked]>
Date: Wed, 24 Apr 2024 11:16:08 +0100

Hi Junio

On 23/04/2024 18:52, Junio C Hamano wrote:
> In the previous step, the "--rfc" option of "format-patch" learned
> to take an optional string value to prepend to the subject prefix,
> so that --rfc=WIP can give "[WIP PATCH]".
> 
> There may be cases in which the extra string wants to come after the
> subject prefix.  Extend the mechanism to allow "--rfc=-(WIP)" [*] to
> signal that the extra string is to be appended instead of getting
> prepended, resulting in "[PATCH (WIP)]".
> 
> In the documentation, discourage (ab)using "--rfc=-RFC" to say
> "[PATCH RFC]" just to be different, when "[RFC PATCH]" is the norm.
> 
> [Footnote]
> 
>   * The syntax takes inspiration from Perl's open syntax that opens
>     pipes "open fh, '|-', 'cmd'", where the dash signals "the other
>     stuff comes here".

I'm not convinced this is a good idea as I'm not sure how adding "RFC" 
at the end of the subject prefix makes the world better than just having 
at the start of the prefix and I find using "-" to do that quite confusing.

Best Wishes

Phillip

> Signed-off-by: Junio C Hamano <[email-masked]>
> ---
>   Documentation/git-format-patch.txt | 6 ++++++
>   builtin/log.c                      | 8 ++++++--
>   t/t4014-format-patch.sh            | 9 +++++++++
>   3 files changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
> index e553810b1e..369af2c4a7 100644
> --- a/Documentation/git-format-patch.txt
> +++ b/Documentation/git-format-patch.txt
> @@ -247,6 +247,12 @@ RFC means "Request For Comments"; use this when sending
>   an experimental patch for discussion rather than application.
>   "--rfc=WIP" may also be a useful way to indicate that a patch
>   is not complete yet ("WIP" stands for "Work In Progress").
> ++
> +If the convention of the receiving community for a particular extra
> +string is to have it _after_ the subject prefix, the string _<rfc>_
> +can be prefixed with a dash ("`-`") to signal that the the rest of
> +the _<rfc>_ string should be appended to the subject prefix instead,
> +e.g., `--rfc='-(WIP)'` results in "PATCH (WIP)".
>   
>   -v <n>::
>   --reroll-count=<n>::
> diff --git a/builtin/log.c b/builtin/log.c
> index 97ca885b33..4750e480e6 100644
> --- a/builtin/log.c
> +++ b/builtin/log.c
> @@ -2065,8 +2065,12 @@ 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 (rfc && rfc[0])
> -		strbuf_insertf(&sprefix, 0, "%s ", rfc);
> +	if (rfc && rfc[0]) {
> +		if (rfc[0] == '-')
> +			strbuf_addf(&sprefix, " %s", rfc + 1);
> +		else
> +			strbuf_insertf(&sprefix, 0, "%s ", rfc);
> +	}
>   
>   	if (reroll_count) {
>   		strbuf_addf(&sprefix, " v%s", reroll_count);
> diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
> index 645c4189f9..fcbde15b16 100755
> --- a/t/t4014-format-patch.sh
> +++ b/t/t4014-format-patch.sh
> @@ -1394,6 +1394,15 @@ test_expect_success '--rfc=WIP and --rfc=' '
>   	test_cmp expect-raw actual
>   '
>   
> +test_expect_success '--rfc=-(WIP) appends' '
> +	cat >expect <<-\EOF &&
> +	Subject: [PATCH (WIP) 1/1] header with . in it
> +	EOF
> +	git format-patch -n -1 --stdout --rfc="-(WIP)" >patch &&
> +	grep "^Subject:" patch >actual &&
> +	test_cmp expect actual
> +'
> +
>   test_expect_success '--rfc does not overwrite prefix' '
>   	cat >expect <<-\EOF &&
>   	Subject: [RFC PATCH foobar 1/1] header with . in it