Re: [PATCH v2 2/3] pretty.c: capture invalid trailer argument

[Junio C Hamano <gitster@pobox.com>]

"Hariom Verma via GitGitGadget" <gitgitgadget@gmail.com> writes:

> +			size_t invalid_arg_len = strcspn(*arg, ",)");
> +			*invalid_arg = xstrndup(*arg, invalid_arg_len);
> +			return 1;

How about doing this only when invalid_arg is not NULL, i.e.

	} else if (!match_placeholder_bool_arg(....) &&
		   ...
        	   !match_placeholder_bool_arg(....)) {
		if (invalid_arg) {
			size_t len = strcspn(*arg, ",)");
			*invalid_arg = xstrndup(*arg, len);
		}
		return -1;
	}

Note that I just used 'len'; when the scope of a variable is so
short, it is clear the length of what thing it refers to from the
context, and there is no point in using a variable name that long.

In any case, by doing so, the callers that are not interested in the
report can just pass NULL, which means ...

> @@ -1464,12 +1472,13 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
>  		struct strbuf sepbuf = STRBUF_INIT;
>  		struct strbuf kvsepbuf = STRBUF_INIT;
>  		size_t ret = 0;
> +		char *unused = NULL;

... this will become unneeded, and ...

>  		opts.no_divider = 1;
>  
>  		if (*arg == ':') {
>  			arg++;
> -			if (format_set_trailers_options(&opts, &filter_list, &sepbuf, &kvsepbuf, &arg))
> +			if (format_set_trailers_options(&opts, &filter_list, &sepbuf, &kvsepbuf, &arg, &unused))
>  				goto trailer_out;

... this will pass NULL, and ...

>  		}
>  		if (*arg == ')') {
> @@ -1479,6 +1488,7 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
>  	trailer_out:
>  		string_list_clear(&filter_list, 0);
>  		strbuf_release(&sepbuf);
> +		free((char *)unused);

... this will become unneeded.

>  		return ret;
>  	}
>  
> diff --git a/pretty.h b/pretty.h
> index 7369cf7e148..d902cdd70a9 100644
> --- a/pretty.h
> +++ b/pretty.h
> @@ -151,6 +151,7 @@ int format_set_trailers_options(struct process_trailer_options *opts,
>  			struct string_list *filter_list,
>  			struct strbuf *sepbuf,
>  			struct strbuf *kvsepbuf,
> -			const char **arg);
> +			const char **arg,
> +			char **invalid_arg);
>  
>  #endif /* PRETTY_H */