+
+int is_range_diff_range(const char *arg)
+{
+ char *copy = xstrdup(arg); /* setup_revisions() modifies it */
+ const char *argv[] = { "", copy, "--", NULL };
+ int i, positive = 0, negative = 0;
+ struct rev_info revs;
+
+ init_revisions(&revs, NULL);
+ if (setup_revisions(3, argv, &revs, NULL) == 1) {
+ for (i = 0; i < revs.pending.nr; i++)
+ if (revs.pending.objects[i].item->flags & UNINTERESTING)
+ negative++;
+ else
+ positive++;
+ for (i = 0; i < revs.pending.nr; i++) {
+ struct object *obj = revs.pending.objects[i].item;
+
+ if (obj->type == OBJ_COMMIT)
+ clear_commit_marks((struct commit *)obj,
+ ALL_REV_FLAGS);
+ }
+ }
+
+ free(copy);
+ object_array_clear(&revs.pending);
+ return negative > 0 && positive > 0;
+}