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

On Mon, Jan 20, 2020 at 11:20 PM Johannes Schindelin
[off-list ref] wrote:

On Mon, 20 Jan 2020, Miriam Rubio wrote:

quoted

@@ -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(...)`.

quoted

      /* 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.