Re: [PATCH 09/29] bisect: libify `check_good_are_ancestors_of_bad` and its dependents

[Christian Couder <christian.couder@gmail.com>]

On Mon, Jan 20, 2020 at 11:20 PM Johannes Schindelin
<Johannes.Schindelin@gmx.de> wrote:
>
> On Mon, 20 Jan 2020, Miriam Rubio wrote:

> > @@ -876,8 +877,15 @@ static void check_good_are_ancestors_of_bad(struct repository *r,
> >       int fd, rev_nr, res = 0;
> >       struct commit **rev;
> >
> > -     if (!current_bad_oid)
> > -             die(_("a %s revision is needed"), term_bad);
> > +     /*
> > +      * We don't want to clean the bisection state
> > +      * as we need to get back to where we started
> > +      * by using `git bisect reset`.
> > +      */
> > +     if (!current_bad_oid) {
> > +             res = error(_("a %s revision is needed"), term_bad);
> > +             goto done;
> > +     }
>
> Why not just return here? Ah, there is a `filename` that was allocated...
> it is too bad that we have a mailing-list based review, as the hunk
> context simply cannot be extended in a mail.
>
> Personally, I think it would be nicer to split the definition of
> `filename` from its declaration and move it _after_ this conditional code,
> so that we can `return` right away.

Yeah, I agree.

> However, there is a more pressing issue than that: `die()` exits with exit
> code 128, so in keeping with the idea to hand down negative exit codes as
> return values, should we not assign `res = -128` here?

I think it has been ok when converting git-bisect.sh to C to just
convert `die(...)` into `return error(...)`.

> >       /* Check if file BISECT_ANCESTORS_OK exists. */
> >       if (!stat(filename, &st) && S_ISREG(st.st_mode))
> > @@ -893,18 +901,20 @@ static void check_good_are_ancestors_of_bad(struct repository *r,
> >       if (check_ancestors(r, rev_nr, rev, prefix))
> >               res = check_merge_bases(rev_nr, rev, no_checkout);
> >       free(rev);
> > -     if(res)
> > -             exit(res == -11 ? 0 : -res);
> > -
> > -     /* Create file BISECT_ANCESTORS_OK. */
> > -     fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
> > -     if (fd < 0)
> > -             warning_errno(_("could not create file '%s'"),
> > -                           filename);
> > -     else
> > -             close(fd);
> > +
> > +     if (!res)
> > +     {
>
> We usually put the `{` on the same line as the `if` condition (like you
> did in the `if (!current_bad_oid)` line above.
>
> The rest looks reasonable. Thank you,

Thank you for your review,
Christian.