Re: [PATCH v16 Part II 5/8] bisect--helper: `bisect_next_check` shell function in C

> @@ -44,6 +46,11 @@ static void set_terms(struct bisect_terms *terms, const char *bad,
>  	terms->term_bad = xstrdup(bad);
>  }
>  
> +static const char *voc[] = {
> +	"bad|new",
> +	"good|old"
> +};
> +
>  /*
>   * Check whether the string `term` belongs to the set of strings
>   * included in the variable arguments.
> @@ -264,6 +271,79 @@ static int check_and_set_terms(struct bisect_terms *terms, const char *cmd)
>  	return 0;
>  }
>  
> +static int mark_good(const char *refname, const struct object_id *oid,
> +		     int flag, void *cb_data)
> +{
> +	int *m_good = (int *)cb_data;
> +	*m_good = 0;
> +	return 1;
> +}
> +
> +static int bisect_next_check(const struct bisect_terms *terms,
> +			     const char *current_term)
> +{
> +	int missing_good = 1, missing_bad = 1, retval = 0;
> +	const char *bad_ref = xstrfmt("refs/bisect/%s", terms->term_bad);
> +	const char *good_glob = xstrfmt("%s-*", terms->term_good);
> +
> +	if (ref_exists(bad_ref))
> +		missing_bad = 0;
> +
> +	for_each_glob_ref_in(mark_good, good_glob, "refs/bisect/",
> +			     (void *) &missing_good);
> +
> +	if (!missing_good && !missing_bad)
> +		goto finish;
> +
> +	if (!current_term)
> +		goto fail;
> +
> +	if (missing_good && !missing_bad && current_term &&
> +	    !strcmp(current_term, terms->term_good)) {
> +		char *yesno;
> +		/*
> +		 * have bad (or new) but not good (or old). We could bisect
> +		 * although this is less optimum.
> +		 */
> +		fprintf(stderr, _("Warning: bisecting only with a %s commit\n"),
> +			terms->term_bad);
> +		if (!isatty(0))
> +			goto finish;
> +		/*
> +		 * TRANSLATORS: Make sure to include [Y] and [n] in your
> +		 * translation. The program will only accept English input
> +		 * at this point.
> +		 */
> +		yesno = git_prompt(_("Are you sure [Y/n]? "), PROMPT_ECHO);
> +		if (starts_with(yesno, "N") || starts_with(yesno, "n"))
> +			goto fail;
> +
> +		goto finish;
> +	}
> +	if (!is_empty_or_missing_file(git_path_bisect_start())) {
> +		error(_("You need to give me at least one %s and "
> +			"%s revision. You can use \"git bisect %s\" "
> +			"and \"git bisect %s\" for that.\n"),
> +			voc[0], voc[1], voc[0], voc[1]);
> +		goto fail;
> +	} else {
> +		error(_("You need to start by \"git bisect start\". You "
> +			"then need to give me at least one %s and %s "
> +			"revision. You can use \"git bisect %s\" and "
> +			"\"git bisect %s\" for that.\n"),
> +			voc[1], voc[0], voc[1], voc[0]);
> +		goto fail;