- /* This part determines what can overwrite what.
- * The rules are:
- *
- * (0) you can always use --force or +A:B notation to
- * selectively force individual ref pairs.
- *
- * (1) if the old thing does not exist, it is OK.
- *
- * (2) if you do not have the old thing, you are not allowed
- * to overwrite it; you would not know what you are losing
- * otherwise.
- *
- * (3) if both new and old are commit-ish, and new is a
- * descendant of old, it is OK.
- *
- * (4) regardless of all of the above, removing :B is
- * always allowed.
- */
-
- ref->nonfastforward =
- !ref->deletion &&
- !is_null_sha1(ref->old_sha1) &&
- (!has_sha1_file(ref->old_sha1)
- || !ref_newer(ref->new_sha1, ref->old_sha1));
-
- if (ref->nonfastforward && !ref->force && !args->force_update) {
- ref->status = REF_STATUS_REJECT_NONFASTFORWARD;