Re: [PATCH 10/29] bisect: libify `handle_bad_merge_base` and its dependents

> From: Pranit Bauva <pranit.bauva@gmail.com>
>
> Since we want to get rid of git-bisect.sh it would be necessary to
> convert those exit() calls to return statements so that errors can be
> reported.
>
> Emulate try catch in C by converting `exit(<positive-value>)` to
> `return <negative-value>`. Follow POSIX conventions to return
> <negative-value> to indicate error.
>
> Turn `exit()` to `return` calls in `handle_bad_merge_base()`.
>
> Handle the return value in dependent function check_merge_bases().

>
> Mentored-by: Christian Couder <chriscool@tuxfamily.org>
> Mentored-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
> Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com>
> Signed-off-by: Tanushree Tumane <tanushreetumane@gmail.com>
> Signed-off-by: Miriam Rubio <mirucam@gmail.com>
> ---
>  bisect.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/bisect.c b/bisect.c
> index 2b80597a1d..acb5a13911 100644
> --- a/bisect.c
> +++ b/bisect.c
> @@ -756,7 +756,7 @@ static struct commit **get_bad_and_good_commits(struct repository *r,
>  	return rev;
>  }
>
> -static void handle_bad_merge_base(void)
> +static int handle_bad_merge_base(void)
>  {
>  	if (is_expected_rev(current_bad_oid)) {
>  		char *bad_hex = oid_to_hex(current_bad_oid);
> @@ -777,14 +777,14 @@ static void handle_bad_merge_base(void)
>  				"between %s and [%s].\n"),
>  				bad_hex, term_bad, term_good, bad_hex, good_hex);
>  		}
> -		exit(3);
> +		return -3;

>  	}
>
>  	fprintf(stderr, _("Some %s revs are not ancestors of the %s rev.\n"
>  		"git bisect cannot work properly in this case.\n"
>  		"Maybe you mistook %s and %s revs?\n"),
>  		term_good, term_bad, term_good, term_bad);
> -	exit(1);
> +	return -1;
>  }
>
>  static void handle_skipped_merge_base(const struct object_id *mb)
> @@ -823,7 +823,8 @@ static int check_merge_bases(int rev_nr, struct commit **rev, int no_checkout)
>  	for (; result; result = result->next) {
>  		const struct object_id *mb = &result->item->object.oid;
>  		if (oideq(mb, current_bad_oid)) {
> -			handle_bad_merge_base();
> +			res = handle_bad_merge_base();
> +			break;
>  		} else if (0 <= oid_array_lookup(&good_revs, mb)) {
>  			continue;
>  		} else if (0 <= oid_array_lookup(&skipped_revs, mb)) {
> --
> 2.21.1 (Apple Git-122.3)
>
>