> Teach Git to write a commit graph file by checking all packed objects > to see if they are commits, then store the file in the given pack > directory. I'm afraid that scanning all packed objects is a bit of a roundabout way to approach this. In my git repo, with 9 pack files at the moment, i.e. not that big a repo and not that many pack files: $ time ./git commit-graph --write --update-head 4df41a3d1cc408b7ad34bea87b51ec4ccbf4b803 real 0m27.550s user 0m27.113s sys 0m0.376s In comparison, performing a good old revision walk to gather all the info that is written into the graph file: $ time git log --all --topo-order --format='%H %T %P %cd' |wc -l 52954 real 0m0.903s user 0m0.972s sys 0m0.058s > +char* get_commit_graph_filename_hash(const char *pack_dir, > + struct object_id *hash) > +{ > + size_t len; > + struct strbuf head_path = STRBUF_INIT; > + strbuf_addstr(&head_path, pack_dir); > + strbuf_addstr(&head_path, "/graph-"); > + strbuf_addstr(&head_path, oid_to_hex(hash)); > + strbuf_addstr(&head_path, ".graph"); Nit: this is assembling the path of a graph file, not that of a graph-head, so the strbuf should be renamed accordingly. > + > + return strbuf_detach(&head_path, &len); > +}