Re: [PATCH v5 5/9] trailer: start preparing for formatting unification

>
> From: Linus Arver <linusa@google.com>
>
> Currently there are two functions for formatting trailers in
> <trailer.h>:
>
>     void format_trailers(const struct process_trailer_options *,
>                          struct list_head *trailers, FILE *outfile);
>
>     void format_trailers_from_commit(struct strbuf *out, const char *msg,
>                                      const struct process_trailer_options *opts);
>
> and although they are similar enough (even taking the same
> process_trailer_options struct pointer) they are used quite differently.
> One might intuitively think that format_trailers_from_commit() builds on
> top of format_trailers(), but this is not the case. Instead
> format_trailers_from_commit() calls format_trailer_info() and
> format_trailers() is never called in that codepath.
>
> This is a preparatory refactor to help us deprecate format_trailers() in
> favor of format_trailer_info() (at which point we can rename the latter
> to the former). When the deprecation is complete, both
> format_trailers_from_commit(), and the interpret-trailers builtin will
> be able to call into the same helper function (instead of
> format_trailers() and format_trailer_info(), respectively). Unifying the
> formatters is desirable because it simplifies the API.
>
> Reorder parameters for format_trailers_from_commit() to prefer
>
>     const struct process_trailer_options *opts
>
> as the first parameter, because these options are intimately tied to
> formatting trailers. And take
>
>     struct strbuf *out
>
> last, because it's an "out parameter" (something that the caller wants
> to use as the output of this function).

> diff --git a/trailer.c b/trailer.c
> index d23afa0a65c..5025be97899 100644
> --- a/trailer.c
> +++ b/trailer.c
> @@ -1083,10 +1083,10 @@ void trailer_info_release(struct trailer_info *info)
>         free(info->trailers);
>  }
>
> -static void format_trailer_info(struct strbuf *out,
> +static void format_trailer_info(const struct process_trailer_options *opts,
>                                 const struct trailer_info *info,
>                                 const char *msg,
> -                               const struct process_trailer_options *opts)
> +                               struct strbuf *out)