Re: [PATCH v8] format-patch: allow a non-integral version numbers

[Eric Sunshine <sunshine@sunshineco.com>]

On Sat, Mar 20, 2021 at 10:56 AM ZheNing Hu via GitGitGadget
<gitgitgadget@gmail.com> wrote:
> diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
> @@ -221,6 +221,11 @@ populated with placeholder text.
> +        `<n>` may be a non-integer number.  E.g. `--reroll-count=4.4`
> +       may produce `v4.4-0001-add-makefile.patch` file that has
> +       "Subject: [PATCH v4.4 1/20] Add makefile" in it.
> +       `--reroll-count=4rev2` may produce `v4rev2-0001-add-makefile.patch`
> +       file that has "Subject: [PATCH v4rev2 1/20] Add makefile" in it.

This new example raises the question about what happens if the
argument to --reroll-count contains characters which don't belong in
pathnames. For instance, what happens if `--reroll-count=1/2` is
specified? Most likely, it will fail trying to write the
"v1/2-whatever.patch" file to a nonexistent directory named "v1".

> diff --git a/log-tree.c b/log-tree.c
> @@ -369,8 +369,8 @@ void fmt_output_subject(struct strbuf *filename,
> +       if (info->reroll_count)
> +               strbuf_addf(filename, "v%s-", info->reroll_count);
>         strbuf_addf(filename, "%04d-%s", nr, subject);

To protect against that problem, you may need to call
format_sanitized_subject() manually after formatting "v%s-". (I'm just
looking at this code for the first time, so I could be hopelessly
wrong. There may be a better way to fix it.)