struct commit_graft *read_graft_line(char *buf, int len);
int register_commit_graft(struct commit_graft *, int);
-struct commit_graft *lookup_commit_graft(const unsigned char *sha1);
+struct commit_graft *lookup_commit_graft(const struct object_id *oid);
extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2);
extern struct commit_list *get_merge_bases_many(struct commit *one, int n, struct commit **twos);