Subject: Re: [PATCH v1 1/6] Allow --porcelain[=<n>] in status and commit commands

From: Johannes Schindelin <[email-masked]>
Date: Wed, 20 Jul 2016 17:08:10 +0200 (CEST)

Hi Jeff,

On Tue, 19 Jul 2016, Jeff Hostetler wrote:

> Update the --porcelain argument to take an optional
> version number.  This will allow us to define new
> porcelain formats in the future.
> 
> This default to 1 and represents the existing porcelain
> format.
> 
> Signed-off-by: Jeff Hostetler <[email-masked]>

Very nice introductory patch.

> diff --git a/builtin/commit.c b/builtin/commit.c
> index 1f6dbcd..892d7f7 100644
> --- a/builtin/commit.c
> +++ b/builtin/commit.c
> @@ -142,14 +142,24 @@ static int show_ignored_in_status, have_option_m;
>  static const char *only_include_assumed;
>  static struct strbuf message = STRBUF_INIT;
>  
> -static enum status_format {
> -	STATUS_FORMAT_NONE = 0,
> -	STATUS_FORMAT_LONG,
> -	STATUS_FORMAT_SHORT,
> -	STATUS_FORMAT_PORCELAIN,
> +static enum wt_status_format status_format = STATUS_FORMAT_UNSPECIFIED;
>  
> -	STATUS_FORMAT_UNSPECIFIED
> -} status_format = STATUS_FORMAT_UNSPECIFIED;
> +static int opt_parse_porcelain(const struct option *opt, const char *arg, int unset)
> +{
> +	enum wt_status_format *value = (enum wt_status_format *)opt->value;
> +	if (unset) {
> +		*value = STATUS_FORMAT_UNSPECIFIED;

In Git's source code, we skip the curly braces for one-liners.

> +	} else if (arg) {
> +		int n = strtol(arg, NULL, 10);
> +		if (n == 1)
> +			*value = STATUS_FORMAT_PORCELAIN;
> +		else
> +			die("unsupported porcelain version");
> +	} else {
> +		*value = STATUS_FORMAT_PORCELAIN;

This could be folded into the previous conditional:

	}
	else {
		int n = arg ? strtol(arg, NULL, 10) : 1;
		...

Having said this, ...

> @@ -1336,9 +1347,9 @@ int cmd_status(int argc, const char **argv, const char *prefix)
>  			    N_("show status concisely"), STATUS_FORMAT_SHORT),
>  		OPT_BOOL('b', "branch", &s.show_branch,
>  			 N_("show branch information")),
> -		OPT_SET_INT(0, "porcelain", &status_format,
> -			    N_("machine-readable output"),
> -			    STATUS_FORMAT_PORCELAIN),
> +		{ OPTION_CALLBACK, 0, "porcelain", &status_format,
> +		  N_("version"), N_("machine-readable output"),
> +		  PARSE_OPT_OPTARG, opt_parse_porcelain },

How about using a COUNTUP here instead? We could then set the status
format afterwards, like this:

	if (porcelain == 0)
		status_format = STATUS_FORMAT_UNSPECIFIED;
	else {
		status_format = STATUS_FORMAT_PORCELAIN;
		if (porcelain > 1)
			warning("No porcelain v%d; falling back to v1",
				porcelain);
	}

The rest of the patch looks good to me!

Ciao,
Johannes