Re: [PATCH v2 2/2] ref-filter: 'contents:trailers' show error if `:` is missing

[Eric Sunshine <sunshine@sunshineco.com>]

On Fri, Aug 21, 2020 at 6:11 AM Hariom Verma via GitGitGadget
<gitgitgadget@gmail.com> wrote:
> The 'contents' atom does not show any error if used with 'trailers'
> atom and semicolon is missing before trailers arguments.

Do you mean s/semicolon/colon/ ?

> e.g %(contents:trailersonly) works, while it shouldn't.
>
> It is definitely not an expected behavior.
>
> Let's fix this bug.
>
> Signed-off-by: Hariom Verma <hariom18599@gmail.com>
> ---
> diff --git a/ref-filter.c b/ref-filter.c
> @@ -332,6 +332,22 @@ static int trailers_atom_parser(const struct ref_format *format, struct used_ato
> +static int check_format_field(const char *arg, const char *field, const char **option)
> +{
> +       const char *opt;
> +       if (skip_prefix(arg, field, &opt)) {
> +               if (*opt == '\0') {
> +                       *option = NULL;
> +                       return 1;
> +               }
> +               else if (*opt == ':') {
> +                       *option = opt + 1;
> +                       return 1;
> +               }
> +       }
> +       return 0;
> +}

Not necessarily worth a re-roll, but rather than introducing all the
above new code...

> @@ -345,9 +361,8 @@ static int contents_atom_parser(const struct ref_format *format, struct used_ato
> -       else if (skip_prefix(arg, "trailers", &arg)) {
> -               skip_prefix(arg, ":", &arg);
> -               if (trailers_atom_parser(format, atom, *arg ? arg : NULL, err))
> +       else if (check_format_field(arg, "trailers", &arg)) {
> +               if (trailers_atom_parser(format, atom, arg, err))
>                         return -1;

...an alternative would have been something like:

    else if (!strcmp(arg, "trailers")) {
        if (trailers_atom_parser(format, atom, NULL, err))
            return -1;
    } else if (skip_prefix(arg, "trailers:", &arg)) {
        if (trailers_atom_parser(format, atom, arg, err))
            return -1;
    }

which is quite simple to reason about (though has the cost of a tiny
bit of duplication).

> diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
> @@ -823,6 +823,15 @@ test_expect_success '%(trailers) rejects unknown trailers arguments' '
> +test_expect_success 'if arguments, %(contents:trailers) shows error if semicolon is missing' '

s/semicolon/colon/

> +       # error message cannot be checked under i18n

What is this comment about? I realize that you copied it from other
nearby tests, but I find that it muddies rather than clarifies.

> +       cat >expect <<-EOF &&
> +       fatal: unrecognized %(contents) argument: trailersonly
> +       EOF
> +       test_must_fail git for-each-ref --format="%(contents:trailersonly)" 2>actual &&
> +       test_i18ncmp expect actual
> +'