This patch confuses me -- see below. > -----Original Message----- > From: Stefan Beller [mailto:sbeller@xxxxxxxxxx] > Sent: Friday, December 02, 2016 7:30 PM > To: bmwill@xxxxxxxxxx; David Turner > Cc: git@xxxxxxxxxxxxxxx; sandals@xxxxxxxxxxxxxxxxxxxx; hvoigt@xxxxxxxxxx; > gitster@xxxxxxxxx; Stefan Beller > Subject: [RFC PATCHv2 09/17] update submodules: add scheduling to update > submodules [snip] > +static int update_submodule(const char *path, const struct object_id > *oid, > + int force, int is_new) > +{ > + const char *git_dir; > + struct child_process cp = CHILD_PROCESS_INIT; > + const struct submodule *sub = submodule_from_path(null_sha1, path); > + > + if (!sub || !sub->name) > + return -1; > + > + git_dir = resolve_gitdir(git_common_path("modules/%s", sub->name)); > + > + if (!git_dir) > + return -1; > + > + if (is_new) > + connect_work_tree_and_git_dir(path, git_dir); > + > + /* update index via `read-tree --reset sha1` */ > + argv_array_pushl(&cp.args, "read-tree", > + force ? "--reset" : "-m", > + "-u", sha1_to_hex(oid->hash), NULL); > + prepare_submodule_repo_env(&cp.env_array); > + cp.git_cmd = 1; > + cp.no_stdin = 1; > + cp.dir = path; > + if (run_command(&cp)) { > + warning(_("reading the index in submodule '%s' failed"), > path); The error is not (usually) in "reading the index" -- it's "updating the index" (or the working tree) > + child_process_clear(&cp); > + return -1; > + } > + > + /* write index to working dir */ > + child_process_clear(&cp); > + child_process_init(&cp); > + argv_array_pushl(&cp.args, "checkout-index", "-a", NULL); I'm confused -- doesn't read-tree -u already do this? And if not, shouldn't we back out the result of the read-tree, to leave the submodule as it was? > + cp.git_cmd = 1; > + cp.no_stdin = 1; > + cp.dir = path; > + if (force) > + argv_array_push(&cp.args, "-f"); > + > + if (run_command(&cp)) { > + warning(_("populating the working directory in submodule '%s' > failed"), path); > + child_process_clear(&cp); > + return -1; > + } > + > + /* get the HEAD right */ > + child_process_clear(&cp); > + child_process_init(&cp); > + argv_array_pushl(&cp.args, "checkout", "--recurse-submodules", > NULL); Why are we running checkout on the submodule when we've already done most of the checkout? The only thing left is to set HEAD and recurse, right? I must be missing something.