Re: [PATCH 2/3] range-diff: handle commit ranges other than A..B

[Eric Sunshine <sunshine@sunshineco.com>]

On Thu, Jan 21, 2021 at 5:22 PM Johannes Schindelin via GitGitGadget
<gitgitgadget@gmail.com> wrote:
> In the `SPECIFYING RANGES` section of gitrevisions[7], two ways are
> described to specify commit ranges that `range-diff` does not yet
> accept: "<commit>^!" and "<commit>^-<n>".
>
> Let's accept them.
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
> diff --git a/builtin/range-diff.c b/builtin/range-diff.c
> @@ -13,7 +13,26 @@ NULL
>  static int is_range(const char *range)
>  {
> +       if (strstr(range, ".."))
> +               return 1;
> +
> +       i = strlen(range);
> +       c = i ? range[--i] : 0;
> +       if (c == '!')
> +               i--; /* might be ...^! or ...^@ */
> +       else if (isdigit(c)) {
> +               /* handle ...^-<n> */
> +               while (i > 2 && isdigit(range[--i]))
> +                       ; /* keep trimming trailing digits */
> +               if (i < 2 || range[i--] != '-')
> +                       return 0;
> +       } else
> +               return 0;
> +
> +       return i > 0 && range[i] == '^';
>  }

Is this something that the --range-diff option of git-format-patch
will want to do, as well? At present,
builtin/log.c:infer_range_diff_ranges() detects a range only by
checking for "..", much like this function did before this patch. If
so, perhaps this function can be part of the public range-diff API
(or, indeed, part of some other more general API if it's not really
specific to range-diff).