extern struct ref **get_remote_heads(int in, struct ref **list, int nr_match, char **match);
extern struct packed_git *parse_pack_index(unsigned char *sha1);
-extern struct packed_git *parse_pack_index_file(unsigned char *sha1,
+extern struct packed_git *parse_pack_index_file(const unsigned char *sha1,
char *idx_path);
extern void prepare_packed_git(void);