extern int register_shallow(const unsigned char *sha1);
extern int unregister_shallow(const unsigned char *sha1);
-extern int write_shallow_commits(struct strbuf *out, int use_pack_protocol);
extern int for_each_commit_graft(each_commit_graft_fn, void *);
extern int is_repository_shallow(void);
extern struct commit_list *get_shallow_commits(struct object_array *heads,