Re: [PATCH v7 3/3] bisect--helper: `write_terms` shell function in C

From: Eric Sunshine <sunshine@sunshineco.com>
Date: May 23, 2016, 16:01 UTC
Message-ID: <CAPig+cSOOv9sGGCTD7=5As9Opu3=e9ofkTpFhCzXC9cJPK21Tg@mail.gmail.com>
In-Reply-To: <1464014928-31548-4-git-send-email-pranit.bauva@gmail.com>

On Mon, May 23, 2016 at 10:48 AM, Pranit Bauva <pranit.bauva@gmail.com> wrote:

Show 23 quoted lines

> Reimplement the `write_terms` shell function in C and add a `write-terms`
> subcommand to `git bisect--helper` to call it from git-bisect.sh . Also
> remove the subcommand `--check-term-format` as it can now be called from
> inside the function write_terms() C implementation.
> [...]
> Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
> ---
> diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
> @@ -56,18 +58,38 @@ static int check_term_format(const char *term, const char *orig_term)
> +static int write_terms(const char *bad, const char *good)
> +{
> +       FILE *fp;
> +       int res;
> +
> +       if (!strcmp(bad, good))
> +               return error(_("please use two different terms"));
> +
> +       if (check_term_format(bad, "bad") || check_term_format(good, "good"))
> +               return -1;
> +
> +       fp = fopen(git_path_bisect_write_terms(), "w");
> +       if (!fp)
> +               return error(_("could not open the file to write terms"));

By adding two pieces of information, you could make this error message much more helpful for anyone trying to debug the failure. Specifically:

(1) the pathname for which open() failed (2) the actual system-level error

For (2), you could use strerror(errno) or, better yet, error_errno() which recently graduated to 'master'.

> +       res = fprintf(fp, "%s\n%s\n", bad, good);
> +       fclose(fp);
> +       return (res < 0) ? -1 : 0;
> +}