text: 
  #include "cache.h"
  #include "repository.h"
  #include "config.h"
  #include "submodule-config.h"
  #include "submodule.h"
  #include "dir.h"
  #include "diff.h"
  #include "commit.h"
  #include "revision.h"
  #include "run-command.h"
  #include "diffcore.h"
  #include "refs.h"
  #include "string-list.h"
  #include "sha1-array.h"
  #include "argv-array.h"
  #include "blob.h"
  #include "thread-utils.h"
  #include "quote.h"
  #include "remote.h"
  #include "worktree.h"
  #include "parse-options.h"
  #include "object-store.h"
  #include "commit-reach.h"
  
  static int config_update_recurse_submodules = RECURSE_SUBMODULES_OFF;
  static int initialized_fetch_ref_tips;
  static struct oid_array ref_tips_before_fetch;
  static struct oid_array ref_tips_after_fetch;
  
  /*
   * Check if the .gitmodules file is unmerged. Parsing of the .gitmodules file
   * will be disabled because we can't guess what might be configured in
   * .gitmodules unless the user resolves the conflict.
   */
  int is_gitmodules_unmerged(const struct index_state *istate)
  {
  	int pos = index_name_pos(istate, GITMODULES_FILE, strlen(GITMODULES_FILE));
  	if (pos < 0) { /* .gitmodules not found or isn't merged */
  		pos = -1 - pos;
  		if (istate->cache_nr > pos) {  /* there is a .gitmodules */
  			const struct cache_entry *ce = istate->cache[pos];
  			if (ce_namelen(ce) == strlen(GITMODULES_FILE) &&
  			    !strcmp(ce->name, GITMODULES_FILE))
  				return 1;
  		}
  	}
  
  	return 0;
  }
  
  /*
   * Check if the .gitmodules file is safe to write.
   *
   * Writing to the .gitmodules file requires that the file exists in the
   * working tree or, if it doesn't, that a brand new .gitmodules file is going
   * to be created (i.e. it's neither in the index nor in the current branch).
   *
   * It is not safe to write to .gitmodules if it's not in the working tree but
   * it is in the index or in the current branch, because writing new values
   * (and staging them) would blindly overwrite ALL the old content.
   */
  int is_writing_gitmodules_ok(void)
  {
  	struct object_id oid;
  	return file_exists(GITMODULES_FILE) ||
  		(get_oid(GITMODULES_INDEX, &oid) < 0 && get_oid(GITMODULES_HEAD, &oid) < 0);
  }
  
  /*
   * Check if the .gitmodules file has unstaged modifications.  This must be
   * checked before allowing modifications to the .gitmodules file with the
   * intention to stage them later, because when continuing we would stage the
   * modifications the user didn't stage herself too. That might change in a
   * future version when we learn to stage the changes we do ourselves without
   * staging any previous modifications.
   */
  int is_staging_gitmodules_ok(struct index_state *istate)
  {
  	int pos = index_name_pos(istate, GITMODULES_FILE, strlen(GITMODULES_FILE));
  
  	if ((pos >= 0) && (pos < istate->cache_nr)) {
  		struct stat st;
  		if (lstat(GITMODULES_FILE, &st) == 0 &&
  		    ie_match_stat(istate, istate->cache[pos], &st, 0) & DATA_CHANGED)
  			return 0;
  	}
  
  	return 1;
  }
  
  static int for_each_remote_ref_submodule(const char *submodule,
  					 each_ref_fn fn, void *cb_data)
  {
  	return refs_for_each_remote_ref(get_submodule_ref_store(submodule),
  					fn, cb_data);
  }
  
  /*
   * Try to update the "path" entry in the "submodule.<name>" section of the
   * .gitmodules file. Return 0 only if a .gitmodules file was found, a section
   * with the correct path=<oldpath> setting was found and we could update it.
   */
  int update_path_in_gitmodules(const char *oldpath, const char *newpath)
  {
  	struct strbuf entry = STRBUF_INIT;
  	const struct submodule *submodule;
  	int ret;
  
  	if (!file_exists(GITMODULES_FILE)) /* Do nothing without .gitmodules */
  		return -1;
  
  	if (is_gitmodules_unmerged(the_repository->index))
  		die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
  
  	submodule = submodule_from_path(the_repository, &null_oid, oldpath);
  	if (!submodule || !submodule->name) {
  		warning(_("Could not find section in .gitmodules where path=%s"), oldpath);
  		return -1;
  	}
  	strbuf_addstr(&entry, "submodule.");
  	strbuf_addstr(&entry, submodule->name);
  	strbuf_addstr(&entry, ".path");
  	ret = config_set_in_gitmodules_file_gently(entry.buf, newpath);
  	strbuf_release(&entry);
  	return ret;
  }
  
  /*
   * Try to remove the "submodule.<name>" section from .gitmodules where the given
   * path is configured. Return 0 only if a .gitmodules file was found, a section
   * with the correct path=<path> setting was found and we could remove it.
   */
  int remove_path_from_gitmodules(const char *path)
  {
  	struct strbuf sect = STRBUF_INIT;
  	const struct submodule *submodule;
  
  	if (!file_exists(GITMODULES_FILE)) /* Do nothing without .gitmodules */
  		return -1;
  
  	if (is_gitmodules_unmerged(the_repository->index))
  		die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
  
  	submodule = submodule_from_path(the_repository, &null_oid, path);
  	if (!submodule || !submodule->name) {
  		warning(_("Could not find section in .gitmodules where path=%s"), path);
  		return -1;
  	}
  	strbuf_addstr(&sect, "submodule.");
  	strbuf_addstr(&sect, submodule->name);
  	if (git_config_rename_section_in_file(GITMODULES_FILE, sect.buf, NULL) < 0) {
  		/* Maybe the user already did that, don't error out here */
  		warning(_("Could not remove .gitmodules entry for %s"), path);
  		strbuf_release(&sect);
  		return -1;
  	}
  	strbuf_release(&sect);
  	return 0;
  }
  
  void stage_updated_gitmodules(struct index_state *istate)
  {
  	if (add_file_to_index(istate, GITMODULES_FILE, 0))
  		die(_("staging updated .gitmodules failed"));
  }
  
  /* TODO: remove this function, use repo_submodule_init instead. */
  int add_submodule_odb(const char *path)
  {
  	struct strbuf objects_directory = STRBUF_INIT;
  	int ret = 0;
  
  	ret = strbuf_git_path_submodule(&objects_directory, path, "objects/");
  	if (ret)
  		goto done;
  	if (!is_directory(objects_directory.buf)) {
  		ret = -1;
  		goto done;
  	}
  	add_to_alternates_memory(objects_directory.buf);
  done:
  	strbuf_release(&objects_directory);
  	return ret;
  }
  
  void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
  					     const char *path)
  {
  	const struct submodule *submodule = submodule_from_path(the_repository,
  								&null_oid, path);
  	if (submodule) {
  		const char *ignore;
  		char *key;
  
  		key = xstrfmt("submodule.%s.ignore", submodule->name);
  		if (repo_config_get_string_const(the_repository, key, &ignore))
  			ignore = submodule->ignore;
  		free(key);
  
  		if (ignore)
  			handle_ignore_submodules_arg(diffopt, ignore);
  		else if (is_gitmodules_unmerged(the_repository->index))
  			diffopt->flags.ignore_submodules = 1;
  	}
  }
  
  /* Cheap function that only determines if we're interested in submodules at all */
  int git_default_submodule_config(const char *var, const char *value, void *cb)
  {
  	if (!strcmp(var, "submodule.recurse")) {
  		int v = git_config_bool(var, value) ?
  			RECURSE_SUBMODULES_ON : RECURSE_SUBMODULES_OFF;
  		config_update_recurse_submodules = v;
  	}
  	return 0;
  }
  
  int option_parse_recurse_submodules_worktree_updater(const struct option *opt,
  						     const char *arg, int unset)
  {
  	if (unset) {
  		config_update_recurse_submodules = RECURSE_SUBMODULES_OFF;
  		return 0;
  	}
  	if (arg)
  		config_update_recurse_submodules =
  			parse_update_recurse_submodules_arg(opt->long_name,
  							    arg);
  	else
  		config_update_recurse_submodules = RECURSE_SUBMODULES_ON;
  
  	return 0;
  }
  
  /*
   * Determine if a submodule has been initialized at a given 'path'
   */
  int is_submodule_active(struct repository *repo, const char *path)
  {
  	int ret = 0;
  	char *key = NULL;
  	char *value = NULL;
  	const struct string_list *sl;
  	const struct submodule *module;
  
  	module = submodule_from_path(repo, &null_oid, path);
  
  	/* early return if there isn't a path->module mapping */
  	if (!module)
  		return 0;
  
  	/* submodule.<name>.active is set */
  	key = xstrfmt("submodule.%s.active", module->name);
  	if (!repo_config_get_bool(repo, key, &ret)) {
  		free(key);
  		return ret;
  	}
  	free(key);
  
  	/* submodule.active is set */
  	sl = repo_config_get_value_multi(repo, "submodule.active");
  	if (sl) {
  		struct pathspec ps;
  		struct argv_array args = ARGV_ARRAY_INIT;
  		const struct string_list_item *item;
  
  		for_each_string_list_item(item, sl) {
  			argv_array_push(&args, item->string);
  		}
  
  		parse_pathspec(&ps, 0, 0, NULL, args.argv);
  		ret = match_pathspec(repo->index, &ps, path, strlen(path), 0, NULL, 1);
  
  		argv_array_clear(&args);
  		clear_pathspec(&ps);
  		return ret;
  	}
  
  	/* fallback to checking if the URL is set */
  	key = xstrfmt("submodule.%s.url", module->name);
  	ret = !repo_config_get_string(repo, key, &value);
  
  	free(value);
  	free(key);
  	return ret;
  }
  
  int is_submodule_populated_gently(const char *path, int *return_error_code)
  {
  	int ret = 0;
  	char *gitdir = xstrfmt("%s/.git", path);
  
  	if (resolve_gitdir_gently(gitdir, return_error_code))
  		ret = 1;
  
  	free(gitdir);
  	return ret;
  }
  
  /*
   * Dies if the provided 'prefix' corresponds to an unpopulated submodule
   */
  void die_in_unpopulated_submodule(const struct index_state *istate,
  				  const char *prefix)
  {
  	int i, prefixlen;
  
  	if (!prefix)
  		return;
  
  	prefixlen = strlen(prefix);
  
  	for (i = 0; i < istate->cache_nr; i++) {
  		struct cache_entry *ce = istate->cache[i];
  		int ce_len = ce_namelen(ce);
  
  		if (!S_ISGITLINK(ce->ce_mode))
  			continue;
  		if (prefixlen <= ce_len)
  			continue;
  		if (strncmp(ce->name, prefix, ce_len))
  			continue;
  		if (prefix[ce_len] != '/')
  			continue;
  
  		die(_("in unpopulated submodule '%s'"), ce->name);
  	}
  }
  
  /*
   * Dies if any paths in the provided pathspec descends into a submodule
   */
  void die_path_inside_submodule(const struct index_state *istate,
  			       const struct pathspec *ps)
  {
  	int i, j;
  
  	for (i = 0; i < istate->cache_nr; i++) {
  		struct cache_entry *ce = istate->cache[i];
  		int ce_len = ce_namelen(ce);
  
  		if (!S_ISGITLINK(ce->ce_mode))
  			continue;
  
  		for (j = 0; j < ps->nr ; j++) {
  			const struct pathspec_item *item = &ps->items[j];
  
  			if (item->len <= ce_len)
  				continue;
  			if (item->match[ce_len] != '/')
  				continue;
  			if (strncmp(ce->name, item->match, ce_len))
  				continue;
  			if (item->len == ce_len + 1)
  				continue;
  
  			die(_("Pathspec '%s' is in submodule '%.*s'"),
  			    item->original, ce_len, ce->name);
  		}
  	}
  }
  
  enum submodule_update_type parse_submodule_update_type(const char *value)
  {
  	if (!strcmp(value, "none"))
  		return SM_UPDATE_NONE;
  	else if (!strcmp(value, "checkout"))
  		return SM_UPDATE_CHECKOUT;
  	else if (!strcmp(value, "rebase"))
  		return SM_UPDATE_REBASE;
  	else if (!strcmp(value, "merge"))
  		return SM_UPDATE_MERGE;
  	else if (*value == '!')
  		return SM_UPDATE_COMMAND;
  	else
  		return SM_UPDATE_UNSPECIFIED;
  }
  
  int parse_submodule_update_strategy(const char *value,
  		struct submodule_update_strategy *dst)
  {
  	enum submodule_update_type type;
  
  	free((void*)dst->command);
  	dst->command = NULL;
  
  	type = parse_submodule_update_type(value);
  	if (type == SM_UPDATE_UNSPECIFIED)
  		return -1;
  
  	dst->type = type;
  	if (type == SM_UPDATE_COMMAND)
  		dst->command = xstrdup(value + 1);
  
  	return 0;
  }
  
  const char *submodule_strategy_to_string(const struct submodule_update_strategy *s)
  {
  	struct strbuf sb = STRBUF_INIT;
  	switch (s->type) {
  	case SM_UPDATE_CHECKOUT:
  		return "checkout";
  	case SM_UPDATE_MERGE:
  		return "merge";
  	case SM_UPDATE_REBASE:
  		return "rebase";
  	case SM_UPDATE_NONE:
  		return "none";
  	case SM_UPDATE_UNSPECIFIED:
  		return NULL;
  	case SM_UPDATE_COMMAND:
  		strbuf_addf(&sb, "!%s", s->command);
  		return strbuf_detach(&sb, NULL);
  	}
  	return NULL;
  }
  
  void handle_ignore_submodules_arg(struct diff_options *diffopt,
  				  const char *arg)
  {
  	diffopt->flags.ignore_submodules = 0;
  	diffopt->flags.ignore_untracked_in_submodules = 0;
  	diffopt->flags.ignore_dirty_submodules = 0;
  
  	if (!strcmp(arg, "all"))
  		diffopt->flags.ignore_submodules = 1;
  	else if (!strcmp(arg, "untracked"))
  		diffopt->flags.ignore_untracked_in_submodules = 1;
  	else if (!strcmp(arg, "dirty"))
  		diffopt->flags.ignore_dirty_submodules = 1;
  	else if (strcmp(arg, "none"))
  		die("bad --ignore-submodules argument: %s", arg);
  	/*
  	 * Please update _git_status() in git-completion.bash when you
  	 * add new options
  	 */
  }
  
  static int prepare_submodule_summary(struct rev_info *rev, const char *path,
  		struct commit *left, struct commit *right,
  		struct commit_list *merge_bases)
  {
  	struct commit_list *list;
  
  	repo_init_revisions(the_repository, rev, NULL);
  	setup_revisions(0, NULL, rev, NULL);
  	rev->left_right = 1;
  	rev->first_parent_only = 1;
  	left->object.flags |= SYMMETRIC_LEFT;
  	add_pending_object(rev, &left->object, path);
  	add_pending_object(rev, &right->object, path);
  	for (list = merge_bases; list; list = list->next) {
  		list->item->object.flags |= UNINTERESTING;
  		add_pending_object(rev, &list->item->object,
  			oid_to_hex(&list->item->object.oid));
  	}
  	return prepare_revision_walk(rev);
  }
  
  static void print_submodule_summary(struct repository *r, struct rev_info *rev, struct diff_options *o)
  {
  	static const char format[] = "  %m %s";
  	struct strbuf sb = STRBUF_INIT;
  	struct commit *commit;
  
  	while ((commit = get_revision(rev))) {
  		struct pretty_print_context ctx = {0};
  		ctx.date_mode = rev->date_mode;
  		ctx.output_encoding = get_log_output_encoding();
  		strbuf_setlen(&sb, 0);
  		repo_format_commit_message(r, commit, format, &sb,
  				      &ctx);
  		strbuf_addch(&sb, '\n');
  		if (commit->object.flags & SYMMETRIC_LEFT)
  			diff_emit_submodule_del(o, sb.buf);
  		else
  			diff_emit_submodule_add(o, sb.buf);
  	}
  	strbuf_release(&sb);
  }
  
  static void prepare_submodule_repo_env_no_git_dir(struct argv_array *out)
  {
  	const char * const *var;
  
  	for (var = local_repo_env; *var; var++) {
  		if (strcmp(*var, CONFIG_DATA_ENVIRONMENT))
  			argv_array_push(out, *var);
  	}
  }
  
  void prepare_submodule_repo_env(struct argv_array *out)
  {
  	prepare_submodule_repo_env_no_git_dir(out);
  	argv_array_pushf(out, "%s=%s", GIT_DIR_ENVIRONMENT,
  			 DEFAULT_GIT_DIR_ENVIRONMENT);
  }
  
  static void prepare_submodule_repo_env_in_gitdir(struct argv_array *out)
  {
  	prepare_submodule_repo_env_no_git_dir(out);
  	argv_array_pushf(out, "%s=.", GIT_DIR_ENVIRONMENT);
  }
  
  /*
   * Initialize a repository struct for a submodule based on the provided 'path'.
   *
   * Unlike repo_submodule_init, this tolerates submodules not present
   * in .gitmodules. This function exists only to preserve historical behavior,
   *
   * Returns the repository struct on success,
   * NULL when the submodule is not present.
   */
  static struct repository *open_submodule(const char *path)
  {
  	struct strbuf sb = STRBUF_INIT;
  	struct repository *out = xmalloc(sizeof(*out));
  
  	if (submodule_to_gitdir(&sb, path) || repo_init(out, sb.buf, NULL)) {
  		strbuf_release(&sb);
  		free(out);
  		return NULL;
  	}
  
  	/* Mark it as a submodule */
  	out->submodule_prefix = xstrdup(path);
  
  	strbuf_release(&sb);
  	return out;
  }
  
  /*
   * Helper function to display the submodule header line prior to the full
   * summary output.
   *
   * If it can locate the submodule git directory it will create a repository
   * handle for the submodule and lookup both the left and right commits and
   * put them into the left and right pointers.
   */
  static void show_submodule_header(struct diff_options *o,
  		const char *path,
  		struct object_id *one, struct object_id *two,
  		unsigned dirty_submodule,
  		struct repository *sub,
  		struct commit **left, struct commit **right,
  		struct commit_list **merge_bases)
  {
  	const char *message = NULL;
  	struct strbuf sb = STRBUF_INIT;
  	int fast_forward = 0, fast_backward = 0;
  
  	if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
  		diff_emit_submodule_untracked(o, path);
  
  	if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
  		diff_emit_submodule_modified(o, path);
  
  	if (is_null_oid(one))
  		message = "(new submodule)";
  	else if (is_null_oid(two))
  		message = "(submodule deleted)";
  
  	if (!sub) {
  		if (!message)
  			message = "(commits not present)";
  		goto output_header;
  	}
  
  	/*
  	 * Attempt to lookup the commit references, and determine if this is
  	 * a fast forward or fast backwards update.
  	 */
  	*left = lookup_commit_reference(sub, one);
  	*right = lookup_commit_reference(sub, two);
  
  	/*
  	 * Warn about missing commits in the submodule project, but only if
  	 * they aren't null.
  	 */
  	if ((!is_null_oid(one) && !*left) ||
  	     (!is_null_oid(two) && !*right))
  		message = "(commits not present)";
  
  	*merge_bases = repo_get_merge_bases(sub, *left, *right);
  	if (*merge_bases) {
  		if ((*merge_bases)->item == *left)
  			fast_forward = 1;
  		else if ((*merge_bases)->item == *right)
  			fast_backward = 1;
  	}
  
  	if (oideq(one, two)) {
  		strbuf_release(&sb);
  		return;
  	}
  
  output_header:
  	strbuf_addf(&sb, "Submodule %s ", path);
  	strbuf_add_unique_abbrev(&sb, one, DEFAULT_ABBREV);
  	strbuf_addstr(&sb, (fast_backward || fast_forward) ? ".." : "...");
  	strbuf_add_unique_abbrev(&sb, two, DEFAULT_ABBREV);
  	if (message)
  		strbuf_addf(&sb, " %s\n", message);
  	else
  		strbuf_addf(&sb, "%s:\n", fast_backward ? " (rewind)" : "");
  	diff_emit_submodule_header(o, sb.buf);
  
  	strbuf_release(&sb);
  }
  
  void show_submodule_summary(struct diff_options *o, const char *path,
  		struct object_id *one, struct object_id *two,
  		unsigned dirty_submodule)
  {
  	struct rev_info rev;
  	struct commit *left = NULL, *right = NULL;
  	struct commit_list *merge_bases = NULL;
  	struct repository *sub;
  
  	sub = open_submodule(path);
  	show_submodule_header(o, path, one, two, dirty_submodule,
  			      sub, &left, &right, &merge_bases);
  
  	/*
  	 * If we don't have both a left and a right pointer, there is no
  	 * reason to try and display a summary. The header line should contain
  	 * all the information the user needs.
  	 */
  	if (!left || !right || !sub)
  		goto out;
  
  	/* Treat revision walker failure the same as missing commits */
  	if (prepare_submodule_summary(&rev, path, left, right, merge_bases)) {
  		diff_emit_submodule_error(o, "(revision walker failed)\n");
  		goto out;
  	}
  
  	print_submodule_summary(sub, &rev, o);
  
  out:
  	if (merge_bases)
  		free_commit_list(merge_bases);
  	clear_commit_marks(left, ~0);
  	clear_commit_marks(right, ~0);
  	if (sub) {
  		repo_clear(sub);
  		free(sub);
  	}
  }
  
  void show_submodule_inline_diff(struct diff_options *o, const char *path,
  		struct object_id *one, struct object_id *two,
  		unsigned dirty_submodule)
  {
  	const struct object_id *old_oid = the_hash_algo->empty_tree, *new_oid = the_hash_algo->empty_tree;
  	struct commit *left = NULL, *right = NULL;
  	struct commit_list *merge_bases = NULL;
  	struct child_process cp = CHILD_PROCESS_INIT;
  	struct strbuf sb = STRBUF_INIT;
  	struct repository *sub;
  
  	sub = open_submodule(path);
  	show_submodule_header(o, path, one, two, dirty_submodule,
  			      sub, &left, &right, &merge_bases);
  
  	/* We need a valid left and right commit to display a difference */
  	if (!(left || is_null_oid(one)) ||
  	    !(right || is_null_oid(two)))
  		goto done;
  
  	if (left)
  		old_oid = one;
  	if (right)
  		new_oid = two;
  
  	cp.git_cmd = 1;
  	cp.dir = path;
  	cp.out = -1;
  	cp.no_stdin = 1;
  
  	/* TODO: other options may need to be passed here. */
  	argv_array_pushl(&cp.args, "diff", "--submodule=diff", NULL);
  	argv_array_pushf(&cp.args, "--color=%s", want_color(o->use_color) ?
  			 "always" : "never");
  
  	if (o->flags.reverse_diff) {
  		argv_array_pushf(&cp.args, "--src-prefix=%s%s/",
  				 o->b_prefix, path);
  		argv_array_pushf(&cp.args, "--dst-prefix=%s%s/",
  				 o->a_prefix, path);
  	} else {
  		argv_array_pushf(&cp.args, "--src-prefix=%s%s/",
  				 o->a_prefix, path);
  		argv_array_pushf(&cp.args, "--dst-prefix=%s%s/",
  				 o->b_prefix, path);
  	}
  	argv_array_push(&cp.args, oid_to_hex(old_oid));
  	/*
  	 * If the submodule has modified content, we will diff against the
  	 * work tree, under the assumption that the user has asked for the
  	 * diff format and wishes to actually see all differences even if they
  	 * haven't yet been committed to the submodule yet.
  	 */
  	if (!(dirty_submodule & DIRTY_SUBMODULE_MODIFIED))
  		argv_array_push(&cp.args, oid_to_hex(new_oid));
  
  	prepare_submodule_repo_env(&cp.env_array);
  	if (start_command(&cp))
  		diff_emit_submodule_error(o, "(diff failed)\n");
  
  	while (strbuf_getwholeline_fd(&sb, cp.out, '\n') != EOF)
  		diff_emit_submodule_pipethrough(o, sb.buf, sb.len);
  
  	if (finish_command(&cp))
  		diff_emit_submodule_error(o, "(diff failed)\n");
  
  done:
  	strbuf_release(&sb);
  	if (merge_bases)
  		free_commit_list(merge_bases);
  	if (left)
  		clear_commit_marks(left, ~0);
  	if (right)
  		clear_commit_marks(right, ~0);
  	if (sub) {
  		repo_clear(sub);
  		free(sub);
  	}
  }
  
  int should_update_submodules(void)
  {
  	return config_update_recurse_submodules == RECURSE_SUBMODULES_ON;
  }
  
  const struct submodule *submodule_from_ce(const struct cache_entry *ce)
  {
  	if (!S_ISGITLINK(ce->ce_mode))
  		return NULL;
  
  	if (!should_update_submodules())
  		return NULL;
  
  	return submodule_from_path(the_repository, &null_oid, ce->name);
  }
  
  static struct oid_array *submodule_commits(struct string_list *submodules,
  					   const char *name)
  {
  	struct string_list_item *item;
  
  	item = string_list_insert(submodules, name);
  	if (item->util)
  		return (struct oid_array *) item->util;
  
  	/* NEEDSWORK: should we have oid_array_init()? */
  	item->util = xcalloc(1, sizeof(struct oid_array));
  	return (struct oid_array *) item->util;
  }
  
  struct collect_changed_submodules_cb_data {
  	struct repository *repo;
  	struct string_list *changed;
  	const struct object_id *commit_oid;
  };
  
  /*
   * this would normally be two functions: default_name_from_path() and
   * path_from_default_name(). Since the default name is the same as
   * the submodule path we can get away with just one function which only
   * checks whether there is a submodule in the working directory at that
   * location.
   */
  static const char *default_name_or_path(const char *path_or_name)
  {
  	int error_code;
  
  	if (!is_submodule_populated_gently(path_or_name, &error_code))
  		return NULL;
  
  	return path_or_name;
  }
  
  static void collect_changed_submodules_cb(struct diff_queue_struct *q,
  					  struct diff_options *options,
  					  void *data)
  {
  	struct collect_changed_submodules_cb_data *me = data;
  	struct string_list *changed = me->changed;
  	const struct object_id *commit_oid = me->commit_oid;
  	int i;
  
  	for (i = 0; i < q->nr; i++) {
  		struct diff_filepair *p = q->queue[i];
  		struct oid_array *commits;
  		const struct submodule *submodule;
  		const char *name;
  
  		if (!S_ISGITLINK(p->two->mode))
  			continue;
  
  		submodule = submodule_from_path(me->repo,
  						commit_oid, p->two->path);
  		if (submodule)
  			name = submodule->name;
  		else {
  			name = default_name_or_path(p->two->path);
  			/* make sure name does not collide with existing one */
  			if (name)
  				submodule = submodule_from_name(me->repo,
  								commit_oid, name);
  			if (submodule) {
  				warning("Submodule in commit %s at path: "
  					"'%s' collides with a submodule named "
  					"the same. Skipping it.",
  					oid_to_hex(commit_oid), p->two->path);
  				name = NULL;
  			}
  		}
  
  		if (!name)
  			continue;
  
  		commits = submodule_commits(changed, name);
  		oid_array_append(commits, &p->two->oid);
  	}
  }
  
  /*
   * Collect the paths of submodules in 'changed' which have changed based on
   * the revisions as specified in 'argv'.  Each entry in 'changed' will also
   * have a corresponding 'struct oid_array' (in the 'util' field) which lists
   * what the submodule pointers were updated to during the change.
   */
  static void collect_changed_submodules(struct repository *r,
  				       struct string_list *changed,
  				       struct argv_array *argv)
  {
  	struct rev_info rev;
  	const struct commit *commit;
  
  	repo_init_revisions(r, &rev, NULL);
  	setup_revisions(argv->argc, argv->argv, &rev, NULL);
  	if (prepare_revision_walk(&rev))
  		die("revision walk setup failed");
  
  	while ((commit = get_revision(&rev))) {
  		struct rev_info diff_rev;
  		struct collect_changed_submodules_cb_data data;
  		data.repo = r;
  		data.changed = changed;
  		data.commit_oid = &commit->object.oid;
  
  		repo_init_revisions(r, &diff_rev, NULL);
  		diff_rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
  		diff_rev.diffopt.format_callback = collect_changed_submodules_cb;
  		diff_rev.diffopt.format_callback_data = &data;
  		diff_tree_combined_merge(commit, 1, &diff_rev);
  	}
  
  	reset_revision_walk();
  }
  
  static void free_submodules_oids(struct string_list *submodules)
  {
  	struct string_list_item *item;
  	for_each_string_list_item(item, submodules)
  		oid_array_clear((struct oid_array *) item->util);
  	string_list_clear(submodules, 1);
  }
  
  static int has_remote(const char *refname, const struct object_id *oid,
  		      int flags, void *cb_data)
  {
  	return 1;
  }
  
  static int append_oid_to_argv(const struct object_id *oid, void *data)
  {
  	struct argv_array *argv = data;
  	argv_array_push(argv, oid_to_hex(oid));
  	return 0;
  }
  
  struct has_commit_data {
  	struct repository *repo;
  	int result;
  	const char *path;
  };
  
  static int check_has_commit(const struct object_id *oid, void *data)
  {
  	struct has_commit_data *cb = data;
  
  	enum object_type type = oid_object_info(cb->repo, oid, NULL);
  
  	switch (type) {
  	case OBJ_COMMIT:
  		return 0;
  	case OBJ_BAD:
  		/*
  		 * Object is missing or invalid. If invalid, an error message
  		 * has already been printed.
  		 */
  		cb->result = 0;
  		return 0;
  	default:
  		die(_("submodule entry '%s' (%s) is a %s, not a commit"),
  		    cb->path, oid_to_hex(oid), type_name(type));
  	}
  }
  
  static int submodule_has_commits(struct repository *r,
  				 const char *path,
  				 struct oid_array *commits)
  {
  	struct has_commit_data has_commit = { r, 1, path };
  
  	/*
  	 * Perform a cheap, but incorrect check for the existence of 'commits'.
  	 * This is done by adding the submodule's object store to the in-core
  	 * object store, and then querying for each commit's existence.  If we
  	 * do not have the commit object anywhere, there is no chance we have
  	 * it in the object store of the correct submodule and have it
  	 * reachable from a ref, so we can fail early without spawning rev-list
  	 * which is expensive.
  	 */
  	if (add_submodule_odb(path))
  		return 0;
  
  	oid_array_for_each_unique(commits, check_has_commit, &has_commit);
  
  	if (has_commit.result) {
  		/*
  		 * Even if the submodule is checked out and the commit is
  		 * present, make sure it exists in the submodule's object store
  		 * and that it is reachable from a ref.
  		 */
  		struct child_process cp = CHILD_PROCESS_INIT;
  		struct strbuf out = STRBUF_INIT;
  
  		argv_array_pushl(&cp.args, "rev-list", "-n", "1", NULL);
  		oid_array_for_each_unique(commits, append_oid_to_argv, &cp.args);
  		argv_array_pushl(&cp.args, "--not", "--all", NULL);
  
  		prepare_submodule_repo_env(&cp.env_array);
  		cp.git_cmd = 1;
  		cp.no_stdin = 1;
  		cp.dir = path;
  
  		if (capture_command(&cp, &out, GIT_MAX_HEXSZ + 1) || out.len)
  			has_commit.result = 0;
  
  		strbuf_release(&out);
  	}
  
  	return has_commit.result;
  }
  
  static int submodule_needs_pushing(struct repository *r,
  				   const char *path,
  				   struct oid_array *commits)
  {
  	if (!submodule_has_commits(r, path, commits))
  		/*
  		 * NOTE: We do consider it safe to return "no" here. The
  		 * correct answer would be "We do not know" instead of
  		 * "No push needed", but it is quite hard to change
  		 * the submodule pointer without having the submodule
  		 * around. If a user did however change the submodules
  		 * without having the submodule around, this indicates
  		 * an expert who knows what they are doing or a
  		 * maintainer integrating work from other people. In
  		 * both cases it should be safe to skip this check.
  		 */
  		return 0;
  
  	if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
  		struct child_process cp = CHILD_PROCESS_INIT;
  		struct strbuf buf = STRBUF_INIT;
  		int needs_pushing = 0;
  
  		argv_array_push(&cp.args, "rev-list");
  		oid_array_for_each_unique(commits, append_oid_to_argv, &cp.args);
  		argv_array_pushl(&cp.args, "--not", "--remotes", "-n", "1" , NULL);
  
  		prepare_submodule_repo_env(&cp.env_array);
  		cp.git_cmd = 1;
  		cp.no_stdin = 1;
  		cp.out = -1;
  		cp.dir = path;
  		if (start_command(&cp))
  			die("Could not run 'git rev-list <commits> --not --remotes -n 1' command in submodule %s",
  					path);
  		if (strbuf_read(&buf, cp.out, the_hash_algo->hexsz + 1))
  			needs_pushing = 1;
  		finish_command(&cp);
  		close(cp.out);
  		strbuf_release(&buf);
  		return needs_pushing;
  	}
  
  	return 0;
  }
  
  int find_unpushed_submodules(struct repository *r,
  			     struct oid_array *commits,
  			     const char *remotes_name,
  			     struct string_list *needs_pushing)
  {
  	struct string_list submodules = STRING_LIST_INIT_DUP;
  	struct string_list_item *name;
  	struct argv_array argv = ARGV_ARRAY_INIT;
  
  	/* argv.argv[0] will be ignored by setup_revisions */
  	argv_array_push(&argv, "find_unpushed_submodules");
  	oid_array_for_each_unique(commits, append_oid_to_argv, &argv);
  	argv_array_push(&argv, "--not");
  	argv_array_pushf(&argv, "--remotes=%s", remotes_name);
  
  	collect_changed_submodules(r, &submodules, &argv);
  
  	for_each_string_list_item(name, &submodules) {
  		struct oid_array *commits = name->util;
  		const struct submodule *submodule;
  		const char *path = NULL;
  
  		submodule = submodule_from_name(r, &null_oid, name->string);
  		if (submodule)
  			path = submodule->path;
  		else
  			path = default_name_or_path(name->string);
  
  		if (!path)
  			continue;
  
  		if (submodule_needs_pushing(r, path, commits))
  			string_list_insert(needs_pushing, path);
  	}
  
  	free_submodules_oids(&submodules);
  	argv_array_clear(&argv);
  
  	return needs_pushing->nr;
  }
  
  static int push_submodule(const char *path,
  			  const struct remote *remote,
  			  const struct refspec *rs,
  			  const struct string_list *push_options,
  			  int dry_run)
  {
  	if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
  		struct child_process cp = CHILD_PROCESS_INIT;
  		argv_array_push(&cp.args, "push");
  		if (dry_run)
  			argv_array_push(&cp.args, "--dry-run");
  
  		if (push_options && push_options->nr) {
  			const struct string_list_item *item;
  			for_each_string_list_item(item, push_options)
  				argv_array_pushf(&cp.args, "--push-option=%s",
  						 item->string);
  		}
  
  		if (remote->origin != REMOTE_UNCONFIGURED) {
  			int i;
  			argv_array_push(&cp.args, remote->name);
  			for (i = 0; i < rs->raw_nr; i++)
  				argv_array_push(&cp.args, rs->raw[i]);
  		}
  
  		prepare_submodule_repo_env(&cp.env_array);
  		cp.git_cmd = 1;
  		cp.no_stdin = 1;
  		cp.dir = path;
  		if (run_command(&cp))
  			return 0;
  		close(cp.out);
  	}
  
  	return 1;
  }
  
  /*
   * Perform a check in the submodule to see if the remote and refspec work.
   * Die if the submodule can't be pushed.
   */
  static void submodule_push_check(const char *path, const char *head,
  				 const struct remote *remote,
  				 const struct refspec *rs)
  {
  	struct child_process cp = CHILD_PROCESS_INIT;
  	int i;
  
  	argv_array_push(&cp.args, "submodule--helper");
  	argv_array_push(&cp.args, "push-check");
  	argv_array_push(&cp.args, head);
  	argv_array_push(&cp.args, remote->name);
  
  	for (i = 0; i < rs->raw_nr; i++)
  		argv_array_push(&cp.args, rs->raw[i]);
  
  	prepare_submodule_repo_env(&cp.env_array);
  	cp.git_cmd = 1;
  	cp.no_stdin = 1;
  	cp.no_stdout = 1;
  	cp.dir = path;
  
  	/*
  	 * Simply indicate if 'submodule--helper push-check' failed.
  	 * More detailed error information will be provided by the
  	 * child process.
  	 */
  	if (run_command(&cp))
  		die("process for submodule '%s' failed", path);
  }
  
  int push_unpushed_submodules(struct repository *r,
  			     struct oid_array *commits,
  			     const struct remote *remote,
  			     const struct refspec *rs,
  			     const struct string_list *push_options,
  			     int dry_run)
  {
  	int i, ret = 1;
  	struct string_list needs_pushing = STRING_LIST_INIT_DUP;
  
  	if (!find_unpushed_submodules(r, commits,
  				      remote->name, &needs_pushing))
  		return 1;
  
  	/*
  	 * Verify that the remote and refspec can be propagated to all
  	 * submodules.  This check can be skipped if the remote and refspec
  	 * won't be propagated due to the remote being unconfigured (e.g. a URL
  	 * instead of a remote name).
  	 */
  	if (remote->origin != REMOTE_UNCONFIGURED) {
  		char *head;
  		struct object_id head_oid;
  
  		head = resolve_refdup("HEAD", 0, &head_oid, NULL);
  		if (!head)
  			die(_("Failed to resolve HEAD as a valid ref."));
  
  		for (i = 0; i < needs_pushing.nr; i++)
  			submodule_push_check(needs_pushing.items[i].string,
  					     head, remote, rs);
  		free(head);
  	}
  
  	/* Actually push the submodules */
  	for (i = 0; i < needs_pushing.nr; i++) {
  		const char *path = needs_pushing.items[i].string;
  		fprintf(stderr, "Pushing submodule '%s'\n", path);
  		if (!push_submodule(path, remote, rs,
  				    push_options, dry_run)) {
  			fprintf(stderr, "Unable to push submodule '%s'\n", path);
  			ret = 0;
  		}
  	}
  
  	string_list_clear(&needs_pushing, 0);
  
  	return ret;
  }
  
  static int append_oid_to_array(const char *ref, const struct object_id *oid,
  			       int flags, void *data)
  {
  	struct oid_array *array = data;
  	oid_array_append(array, oid);
  	return 0;
  }
  
  void check_for_new_submodule_commits(struct object_id *oid)
  {
  	if (!initialized_fetch_ref_tips) {
  		for_each_ref(append_oid_to_array, &ref_tips_before_fetch);
  		initialized_fetch_ref_tips = 1;
  	}
  
  	oid_array_append(&ref_tips_after_fetch, oid);
  }
  
  static void calculate_changed_submodule_paths(struct repository *r,
  		struct string_list *changed_submodule_names)
  {
  	struct argv_array argv = ARGV_ARRAY_INIT;
  	struct string_list_item *name;
  
  	/* No need to check if there are no submodules configured */
  	if (!submodule_from_path(r, NULL, NULL))
  		return;
  
  	argv_array_push(&argv, "--"); /* argv[0] program name */
  	oid_array_for_each_unique(&ref_tips_after_fetch,
  				   append_oid_to_argv, &argv);
  	argv_array_push(&argv, "--not");
  	oid_array_for_each_unique(&ref_tips_before_fetch,
  				   append_oid_to_argv, &argv);
  
  	/*
  	 * Collect all submodules (whether checked out or not) for which new
  	 * commits have been recorded upstream in "changed_submodule_names".
  	 */
  	collect_changed_submodules(r, changed_submodule_names, &argv);
  
  	for_each_string_list_item(name, changed_submodule_names) {
  		struct oid_array *commits = name->util;
  		const struct submodule *submodule;
  		const char *path = NULL;
  
  		submodule = submodule_from_name(r, &null_oid, name->string);
  		if (submodule)
  			path = submodule->path;
  		else
  			path = default_name_or_path(name->string);
  
  		if (!path)
  			continue;
  
  		if (submodule_has_commits(r, path, commits)) {
  			oid_array_clear(commits);
  			*name->string = '\0';
  		}
  	}
  
  	string_list_remove_empty_items(changed_submodule_names, 1);
  
  	argv_array_clear(&argv);
  	oid_array_clear(&ref_tips_before_fetch);
  	oid_array_clear(&ref_tips_after_fetch);
  	initialized_fetch_ref_tips = 0;
  }
  
  int submodule_touches_in_range(struct repository *r,
  			       struct object_id *excl_oid,
  			       struct object_id *incl_oid)
  {
  	struct string_list subs = STRING_LIST_INIT_DUP;
  	struct argv_array args = ARGV_ARRAY_INIT;
  	int ret;
  
  	/* No need to check if there are no submodules configured */
  	if (!submodule_from_path(r, NULL, NULL))
  		return 0;
  
  	argv_array_push(&args, "--"); /* args[0] program name */
  	argv_array_push(&args, oid_to_hex(incl_oid));
  	if (!is_null_oid(excl_oid)) {
  		argv_array_push(&args, "--not");
  		argv_array_push(&args, oid_to_hex(excl_oid));
  	}
  
  	collect_changed_submodules(r, &subs, &args);
  	ret = subs.nr;
  
  	argv_array_clear(&args);
  
  	free_submodules_oids(&subs);
  	return ret;
  }
  
  struct submodule_parallel_fetch {
  	int count;
  	struct argv_array args;
  	struct repository *r;
  	const char *prefix;
  	int command_line_option;
  	int default_option;
  	int quiet;
  	int result;
  
  	struct string_list changed_submodule_names;
  
  	/* Pending fetches by OIDs */
  	struct fetch_task **oid_fetch_tasks;
  	int oid_fetch_tasks_nr, oid_fetch_tasks_alloc;
  };
  #define SPF_INIT {0, ARGV_ARRAY_INIT, NULL, NULL, 0, 0, 0, 0, \
  		  STRING_LIST_INIT_DUP, \
  		  NULL, 0, 0}
  
  static int get_fetch_recurse_config(const struct submodule *submodule,
  				    struct submodule_parallel_fetch *spf)
  {
  	if (spf->command_line_option != RECURSE_SUBMODULES_DEFAULT)
  		return spf->command_line_option;
  
  	if (submodule) {
  		char *key;
  		const char *value;
  
  		int fetch_recurse = submodule->fetch_recurse;
  		key = xstrfmt("submodule.%s.fetchRecurseSubmodules", submodule->name);
  		if (!repo_config_get_string_const(spf->r, key, &value)) {
  			fetch_recurse = parse_fetch_recurse_submodules_arg(key, value);
  		}
  		free(key);
  
  		if (fetch_recurse != RECURSE_SUBMODULES_NONE)
  			/* local config overrules everything except commandline */
  			return fetch_recurse;
  	}
  
  	return spf->default_option;
  }
  
  /*
   * Fetch in progress (if callback data) or
   * pending (if in oid_fetch_tasks in struct submodule_parallel_fetch)
   */
  struct fetch_task {
  	struct repository *repo;
  	const struct submodule *sub;
  	unsigned free_sub : 1; /* Do we need to free the submodule? */
  
  	struct oid_array *commits; /* Ensure these commits are fetched */
  };
  
  /**
   * When a submodule is not defined in .gitmodules, we cannot access it
   * via the regular submodule-config. Create a fake submodule, which we can
   * work on.
   */
  static const struct submodule *get_non_gitmodules_submodule(const char *path)
  {
  	struct submodule *ret = NULL;
  	const char *name = default_name_or_path(path);
  
  	if (!name)
  		return NULL;
  
  	ret = xmalloc(sizeof(*ret));
  	memset(ret, 0, sizeof(*ret));
  	ret->path = name;
  	ret->name = name;
  
  	return (const struct submodule *) ret;
  }
  
  static struct fetch_task *fetch_task_create(struct repository *r,
  					    const char *path)
  {
  	struct fetch_task *task = xmalloc(sizeof(*task));
  	memset(task, 0, sizeof(*task));
  
  	task->sub = submodule_from_path(r, &null_oid, path);
  	if (!task->sub) {
  		/*
  		 * No entry in .gitmodules? Technically not a submodule,
  		 * but historically we supported repositories that happen to be
  		 * in-place where a gitlink is. Keep supporting them.
  		 */
  		task->sub = get_non_gitmodules_submodule(path);
  		if (!task->sub) {
  			free(task);
  			return NULL;
  		}
  
  		task->free_sub = 1;
  	}
  
  	return task;
  }
  
  static void fetch_task_release(struct fetch_task *p)
  {
  	if (p->free_sub)
  		free((void*)p->sub);
  	p->free_sub = 0;
  	p->sub = NULL;
  
  	if (p->repo)
  		repo_clear(p->repo);
  	FREE_AND_NULL(p->repo);
  }
  
  static struct repository *get_submodule_repo_for(struct repository *r,
  						 const struct submodule *sub)
  {
  	struct repository *ret = xmalloc(sizeof(*ret));
  
  	if (repo_submodule_init(ret, r, sub)) {
  		/*
  		 * No entry in .gitmodules? Technically not a submodule,
  		 * but historically we supported repositories that happen to be
  		 * in-place where a gitlink is. Keep supporting them.
  		 */
  		struct strbuf gitdir = STRBUF_INIT;
  		strbuf_repo_worktree_path(&gitdir, r, "%s/.git", sub->path);
  		if (repo_init(ret, gitdir.buf, NULL)) {
  			strbuf_release(&gitdir);
  			free(ret);
  			return NULL;
  		}
  		strbuf_release(&gitdir);
  	}
  
  	return ret;
  }
  
  static int get_next_submodule(struct child_process *cp,
  			      struct strbuf *err, void *data, void **task_cb)
  {
  	struct submodule_parallel_fetch *spf = data;
  
  	for (; spf->count < spf->r->index->cache_nr; spf->count++) {
  		const struct cache_entry *ce = spf->r->index->cache[spf->count];
  		const char *default_argv;
  		struct fetch_task *task;
  
  		if (!S_ISGITLINK(ce->ce_mode))
  			continue;
  
  		task = fetch_task_create(spf->r, ce->name);
  		if (!task)
  			continue;
  
  		switch (get_fetch_recurse_config(task->sub, spf))
  		{
  		default:
  		case RECURSE_SUBMODULES_DEFAULT:
  		case RECURSE_SUBMODULES_ON_DEMAND:
  			if (!task->sub ||
  			    !string_list_lookup(
  					&spf->changed_submodule_names,
  					task->sub->name))
  				continue;
  			default_argv = "on-demand";
  			break;
  		case RECURSE_SUBMODULES_ON:
  			default_argv = "yes";
  			break;
  		case RECURSE_SUBMODULES_OFF:
  			continue;
  		}
  
  		task->repo = get_submodule_repo_for(spf->r, task->sub);
  		if (task->repo) {
  			struct strbuf submodule_prefix = STRBUF_INIT;
  			child_process_init(cp);
  			cp->dir = task->repo->gitdir;
  			prepare_submodule_repo_env_in_gitdir(&cp->env_array);
  			cp->git_cmd = 1;
  			if (!spf->quiet)
  				strbuf_addf(err, "Fetching submodule %s%s\n",
  					    spf->prefix, ce->name);
  			argv_array_init(&cp->args);
  			argv_array_pushv(&cp->args, spf->args.argv);
  			argv_array_push(&cp->args, default_argv);
  			argv_array_push(&cp->args, "--submodule-prefix");
  
  			strbuf_addf(&submodule_prefix, "%s%s/",
  						       spf->prefix,
  						       task->sub->path);
  			argv_array_push(&cp->args, submodule_prefix.buf);
  
  			spf->count++;
  			*task_cb = task;
  
  			strbuf_release(&submodule_prefix);
  			return 1;
  		} else {
  
  			fetch_task_release(task);
  			free(task);
  
  			/*
  			 * An empty directory is normal,
  			 * the submodule is not initialized
  			 */
  			if (S_ISGITLINK(ce->ce_mode) &&
  			    !is_empty_dir(ce->name)) {
  				spf->result = 1;
  				strbuf_addf(err,
  					    _("Could not access submodule '%s'"),
  					    ce->name);
  			}
  		}
  	}
  
  	if (spf->oid_fetch_tasks_nr) {
  		struct fetch_task *task =
  			spf->oid_fetch_tasks[spf->oid_fetch_tasks_nr - 1];
  		struct strbuf submodule_prefix = STRBUF_INIT;
  		spf->oid_fetch_tasks_nr--;
  
  		strbuf_addf(&submodule_prefix, "%s%s/",
  			    spf->prefix, task->sub->path);
  
  		child_process_init(cp);
  		prepare_submodule_repo_env_in_gitdir(&cp->env_array);
  		cp->git_cmd = 1;
  		cp->dir = task->repo->gitdir;
  
  		argv_array_init(&cp->args);
  		argv_array_pushv(&cp->args, spf->args.argv);
  		argv_array_push(&cp->args, "on-demand");
  		argv_array_push(&cp->args, "--submodule-prefix");
  		argv_array_push(&cp->args, submodule_prefix.buf);
  
  		/* NEEDSWORK: have get_default_remote from submodule--helper */
  		argv_array_push(&cp->args, "origin");
  		oid_array_for_each_unique(task->commits,
  					  append_oid_to_argv, &cp->args);
  
  		*task_cb = task;
  		strbuf_release(&submodule_prefix);
  		return 1;
  	}
  
  	return 0;
  }
  
  static int fetch_start_failure(struct strbuf *err,
  			       void *cb, void *task_cb)
  {
  	struct submodule_parallel_fetch *spf = cb;
  	struct fetch_task *task = task_cb;
  
  	spf->result = 1;
  
  	fetch_task_release(task);
  	return 0;
  }
  
  static int commit_missing_in_sub(const struct object_id *oid, void *data)
  {
  	struct repository *subrepo = data;
  
  	enum object_type type = oid_object_info(subrepo, oid, NULL);
  
  	return type != OBJ_COMMIT;
  }
  
  static int fetch_finish(int retvalue, struct strbuf *err,
  			void *cb, void *task_cb)
  {
  	struct submodule_parallel_fetch *spf = cb;
  	struct fetch_task *task = task_cb;
  
  	struct string_list_item *it;
  	struct oid_array *commits;
  
  	if (retvalue)
  		/*
  		 * NEEDSWORK: This indicates that the overall fetch
  		 * failed, even though there may be a subsequent fetch
  		 * by commit hash that might work. It may be a good
  		 * idea to not indicate failure in this case, and only
  		 * indicate failure if the subsequent fetch fails.
  		 */
  		spf->result = 1;
  
  	if (!task || !task->sub)
  		BUG("callback cookie bogus");
  
  	/* Is this the second time we process this submodule? */
  	if (task->commits)
  		goto out;
  
  	it = string_list_lookup(&spf->changed_submodule_names, task->sub->name);
  	if (!it)
  		/* Could be an unchanged submodule, not contained in the list */
  		goto out;
  
  	commits = it->util;
  	oid_array_filter(commits,
  			 commit_missing_in_sub,
  			 task->repo);
  
  	/* Are there commits we want, but do not exist? */
  	if (commits->nr) {
  		task->commits = commits;
  		ALLOC_GROW(spf->oid_fetch_tasks,
  			   spf->oid_fetch_tasks_nr + 1,
  			   spf->oid_fetch_tasks_alloc);
  		spf->oid_fetch_tasks[spf->oid_fetch_tasks_nr] = task;
  		spf->oid_fetch_tasks_nr++;
  		return 0;
  	}
  
  out:
  	fetch_task_release(task);
  
  	return 0;
  }
  
  int fetch_populated_submodules(struct repository *r,
  			       const struct argv_array *options,
  			       const char *prefix, int command_line_option,
  			       int default_option,
  			       int quiet, int max_parallel_jobs)
  {
  	int i;
  	struct submodule_parallel_fetch spf = SPF_INIT;
  
  	spf.r = r;
  	spf.command_line_option = command_line_option;
  	spf.default_option = default_option;
  	spf.quiet = quiet;
  	spf.prefix = prefix;
  
  	if (!r->worktree)
  		goto out;
  
  	if (repo_read_index(r) < 0)
  		die("index file corrupt");
  
  	argv_array_push(&spf.args, "fetch");
  	for (i = 0; i < options->argc; i++)
  		argv_array_push(&spf.args, options->argv[i]);
  	argv_array_push(&spf.args, "--recurse-submodules-default");
  	/* default value, "--submodule-prefix" and its value are added later */
  
  	calculate_changed_submodule_paths(r, &spf.changed_submodule_names);
  	string_list_sort(&spf.changed_submodule_names);
  	run_processes_parallel_tr2(max_parallel_jobs,
  				   get_next_submodule,
  				   fetch_start_failure,
  				   fetch_finish,
  				   &spf,
  				   "submodule", "parallel/fetch");
  
  	argv_array_clear(&spf.args);
  out:
  	free_submodules_oids(&spf.changed_submodule_names);
  	return spf.result;
  }
  
  unsigned is_submodule_modified(const char *path, int ignore_untracked)
  {
  	struct child_process cp = CHILD_PROCESS_INIT;
  	struct strbuf buf = STRBUF_INIT;
  	FILE *fp;
  	unsigned dirty_submodule = 0;
  	const char *git_dir;
  	int ignore_cp_exit_code = 0;
  
  	strbuf_addf(&buf, "%s/.git", path);
  	git_dir = read_gitfile(buf.buf);
  	if (!git_dir)
  		git_dir = buf.buf;
  	if (!is_git_directory(git_dir)) {
  		if (is_directory(git_dir))
  			die(_("'%s' not recognized as a git repository"), git_dir);
  		strbuf_release(&buf);
  		/* The submodule is not checked out, so it is not modified */
  		return 0;
  	}
  	strbuf_reset(&buf);
  
  	argv_array_pushl(&cp.args, "status", "--porcelain=2", NULL);
  	if (ignore_untracked)
  		argv_array_push(&cp.args, "-uno");
  
  	prepare_submodule_repo_env(&cp.env_array);
  	cp.git_cmd = 1;
  	cp.no_stdin = 1;
  	cp.out = -1;
  	cp.dir = path;
  	if (start_command(&cp))
  		die("Could not run 'git status --porcelain=2' in submodule %s", path);
  
  	fp = xfdopen(cp.out, "r");
  	while (strbuf_getwholeline(&buf, fp, '\n') != EOF) {
  		/* regular untracked files */
  		if (buf.buf[0] == '?')
  			dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
  
  		if (buf.buf[0] == 'u' ||
  		    buf.buf[0] == '1' ||
  		    buf.buf[0] == '2') {
  			/* T = line type, XY = status, SSSS = submodule state */
  			if (buf.len < strlen("T XY SSSS"))
  				BUG("invalid status --porcelain=2 line %s",
  				    buf.buf);
  
  			if (buf.buf[5] == 'S' && buf.buf[8] == 'U')
  				/* nested untracked file */
  				dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
  
  			if (buf.buf[0] == 'u' ||
  			    buf.buf[0] == '2' ||
  			    memcmp(buf.buf + 5, "S..U", 4))
  				/* other change */
  				dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
  		}
  
  		if ((dirty_submodule & DIRTY_SUBMODULE_MODIFIED) &&
  		    ((dirty_submodule & DIRTY_SUBMODULE_UNTRACKED) ||
  		     ignore_untracked)) {
  			/*
  			 * We're not interested in any further information from
  			 * the child any more, neither output nor its exit code.
  			 */
  			ignore_cp_exit_code = 1;
  			break;
  		}
  	}
  	fclose(fp);
  
  	if (finish_command(&cp) && !ignore_cp_exit_code)
  		die("'git status --porcelain=2' failed in submodule %s", path);
  
  	strbuf_release(&buf);
  	return dirty_submodule;
  }
  
  int submodule_uses_gitfile(const char *path)
  {
  	struct child_process cp = CHILD_PROCESS_INIT;
  	const char *argv[] = {
  		"submodule",
  		"foreach",
  		"--quiet",
  		"--recursive",
  		"test -f .git",
  		NULL,
  	};
  	struct strbuf buf = STRBUF_INIT;
  	const char *git_dir;
  
  	strbuf_addf(&buf, "%s/.git", path);
  	git_dir = read_gitfile(buf.buf);
  	if (!git_dir) {
  		strbuf_release(&buf);
  		return 0;
  	}
  	strbuf_release(&buf);
  
  	/* Now test that all nested submodules use a gitfile too */
  	cp.argv = argv;
  	prepare_submodule_repo_env(&cp.env_array);
  	cp.git_cmd = 1;
  	cp.no_stdin = 1;
  	cp.no_stderr = 1;
  	cp.no_stdout = 1;
  	cp.dir = path;
  	if (run_command(&cp))
  		return 0;
  
  	return 1;
  }
  
  /*
   * Check if it is a bad idea to remove a submodule, i.e. if we'd lose data
   * when doing so.
   *
   * Return 1 if we'd lose data, return 0 if the removal is fine,
   * and negative values for errors.
   */
  int bad_to_remove_submodule(const char *path, unsigned flags)
  {
  	ssize_t len;
  	struct child_process cp = CHILD_PROCESS_INIT;
  	struct strbuf buf = STRBUF_INIT;
  	int ret = 0;
  
  	if (!file_exists(path) || is_empty_dir(path))
  		return 0;
  
  	if (!submodule_uses_gitfile(path))
  		return 1;
  
  	argv_array_pushl(&cp.args, "status", "--porcelain",
  				   "--ignore-submodules=none", NULL);
  
  	if (flags & SUBMODULE_REMOVAL_IGNORE_UNTRACKED)
  		argv_array_push(&cp.args, "-uno");
  	else
  		argv_array_push(&cp.args, "-uall");
  
  	if (!(flags & SUBMODULE_REMOVAL_IGNORE_IGNORED_UNTRACKED))
  		argv_array_push(&cp.args, "--ignored");
  
  	prepare_submodule_repo_env(&cp.env_array);
  	cp.git_cmd = 1;
  	cp.no_stdin = 1;
  	cp.out = -1;
  	cp.dir = path;
  	if (start_command(&cp)) {
  		if (flags & SUBMODULE_REMOVAL_DIE_ON_ERROR)
  			die(_("could not start 'git status' in submodule '%s'"),
  				path);
  		ret = -1;
  		goto out;
  	}
  
  	len = strbuf_read(&buf, cp.out, 1024);
  	if (len > 2)
  		ret = 1;
  	close(cp.out);
  
  	if (finish_command(&cp)) {
  		if (flags & SUBMODULE_REMOVAL_DIE_ON_ERROR)
  			die(_("could not run 'git status' in submodule '%s'"),
  				path);
  		ret = -1;
  	}
  out:
  	strbuf_release(&buf);
  	return ret;
  }
  
  void submodule_unset_core_worktree(const struct submodule *sub)
  {
  	char *config_path = xstrfmt("%s/modules/%s/config",
  				    get_git_common_dir(), sub->name);
  
  	if (git_config_set_in_file_gently(config_path, "core.worktree", NULL))
  		warning(_("Could not unset core.worktree setting in submodule '%s'"),
  			  sub->path);
  
  	free(config_path);
  }
  
  static const char *get_super_prefix_or_empty(void)
  {
  	const char *s = get_super_prefix();
  	if (!s)
  		s = "";
  	return s;
  }
  
  static int submodule_has_dirty_index(const struct submodule *sub)
  {
  	struct child_process cp = CHILD_PROCESS_INIT;
  
  	prepare_submodule_repo_env(&cp.env_array);
  
  	cp.git_cmd = 1;
  	argv_array_pushl(&cp.args, "diff-index", "--quiet",
  				   "--cached", "HEAD", NULL);
  	cp.no_stdin = 1;
  	cp.no_stdout = 1;
  	cp.dir = sub->path;
  	if (start_command(&cp))
  		die("could not recurse into submodule '%s'", sub->path);
  
  	return finish_command(&cp);
  }
  
  static void submodule_reset_index(const char *path)
  {
  	struct child_process cp = CHILD_PROCESS_INIT;
  	prepare_submodule_repo_env(&cp.env_array);
  
  	cp.git_cmd = 1;
  	cp.no_stdin = 1;
  	cp.dir = path;
  
  	argv_array_pushf(&cp.args, "--super-prefix=%s%s/",
  				   get_super_prefix_or_empty(), path);
  	argv_array_pushl(&cp.args, "read-tree", "-u", "--reset", NULL);
  
  	argv_array_push(&cp.args, empty_tree_oid_hex());
  
  	if (run_command(&cp))
  		die("could not reset submodule index");
  }
  
  /**
   * Moves a submodule at a given path from a given head to another new head.
   * For edge cases (a submodule coming into existence or removing a submodule)
   * pass NULL for old or new respectively.
   */
  int submodule_move_head(const char *path,
  			 const char *old_head,
  			 const char *new_head,
  			 unsigned flags)
  {
  	int ret = 0;
  	struct child_process cp = CHILD_PROCESS_INIT;
  	const struct submodule *sub;
  	int *error_code_ptr, error_code;
  
  	if (!is_submodule_active(the_repository, path))
  		return 0;
  
  	if (flags & SUBMODULE_MOVE_HEAD_FORCE)
  		/*
  		 * Pass non NULL pointer to is_submodule_populated_gently
  		 * to prevent die()-ing. We'll use connect_work_tree_and_git_dir
  		 * to fixup the submodule in the force case later.
  		 */
  		error_code_ptr = &error_code;
  	else
  		error_code_ptr = NULL;
  
  	if (old_head && !is_submodule_populated_gently(path, error_code_ptr))
  		return 0;
  
  	sub = submodule_from_path(the_repository, &null_oid, path);
  
  	if (!sub)
  		BUG("could not get submodule information for '%s'", path);
  
  	if (old_head && !(flags & SUBMODULE_MOVE_HEAD_FORCE)) {
  		/* Check if the submodule has a dirty index. */
  		if (submodule_has_dirty_index(sub))
  			return error(_("submodule '%s' has dirty index"), path);
  	}
  
  	if (!(flags & SUBMODULE_MOVE_HEAD_DRY_RUN)) {
  		if (old_head) {
  			if (!submodule_uses_gitfile(path))
  				absorb_git_dir_into_superproject(path,
  					ABSORB_GITDIR_RECURSE_SUBMODULES);
  		} else {
  			char *gitdir = xstrfmt("%s/modules/%s",
  				    get_git_common_dir(), sub->name);
  			connect_work_tree_and_git_dir(path, gitdir, 0);
  			free(gitdir);
  
  			/* make sure the index is clean as well */
  			submodule_reset_index(path);
  		}
  
  		if (old_head && (flags & SUBMODULE_MOVE_HEAD_FORCE)) {
  			char *gitdir = xstrfmt("%s/modules/%s",
  				    get_git_common_dir(), sub->name);
  			connect_work_tree_and_git_dir(path, gitdir, 1);
  			free(gitdir);
  		}
  	}
  
  	prepare_submodule_repo_env(&cp.env_array);
  
  	cp.git_cmd = 1;
  	cp.no_stdin = 1;
  	cp.dir = path;
  
  	argv_array_pushf(&cp.args, "--super-prefix=%s%s/",
  			get_super_prefix_or_empty(), path);
  	argv_array_pushl(&cp.args, "read-tree", "--recurse-submodules", NULL);
  
  	if (flags & SUBMODULE_MOVE_HEAD_DRY_RUN)
  		argv_array_push(&cp.args, "-n");
  	else
  		argv_array_push(&cp.args, "-u");
  
  	if (flags & SUBMODULE_MOVE_HEAD_FORCE)
  		argv_array_push(&cp.args, "--reset");
  	else
  		argv_array_push(&cp.args, "-m");
  
  	if (!(flags & SUBMODULE_MOVE_HEAD_FORCE))
  		argv_array_push(&cp.args, old_head ? old_head : empty_tree_oid_hex());
  
  	argv_array_push(&cp.args, new_head ? new_head : empty_tree_oid_hex());
  
  	if (run_command(&cp)) {
  		ret = error(_("Submodule '%s' could not be updated."), path);
  		goto out;
  	}
  
  	if (!(flags & SUBMODULE_MOVE_HEAD_DRY_RUN)) {
  		if (new_head) {
  			child_process_init(&cp);
  			/* also set the HEAD accordingly */
  			cp.git_cmd = 1;
  			cp.no_stdin = 1;
  			cp.dir = path;
  
  			prepare_submodule_repo_env(&cp.env_array);
  			argv_array_pushl(&cp.args, "update-ref", "HEAD",
  					 "--no-deref", new_head, NULL);
  
  			if (run_command(&cp)) {
  				ret = -1;
  				goto out;
  			}
  		} else {
  			struct strbuf sb = STRBUF_INIT;
  
  			strbuf_addf(&sb, "%s/.git", path);
  			unlink_or_warn(sb.buf);
  			strbuf_release(&sb);
  
  			if (is_empty_dir(path))
  				rmdir_or_warn(path);
  
  			submodule_unset_core_worktree(sub);
  		}
  	}
  out:
  	return ret;
  }
  
  /*
   * Embeds a single submodules git directory into the superprojects git dir,
   * non recursively.
   */
  static void relocate_single_git_dir_into_superproject(const char *path)
  {
  	char *old_git_dir = NULL, *real_old_git_dir = NULL, *real_new_git_dir = NULL;
  	const char *new_git_dir;
  	const struct submodule *sub;
  
  	if (submodule_uses_worktrees(path))
  		die(_("relocate_gitdir for submodule '%s' with "
  		      "more than one worktree not supported"), path);
  
  	old_git_dir = xstrfmt("%s/.git", path);
  	if (read_gitfile(old_git_dir))
  		/* If it is an actual gitfile, it doesn't need migration. */
  		return;
  
  	real_old_git_dir = real_pathdup(old_git_dir, 1);
  
  	sub = submodule_from_path(the_repository, &null_oid, path);
  	if (!sub)
  		die(_("could not lookup name for submodule '%s'"), path);
  
  	new_git_dir = git_path("modules/%s", sub->name);
  	if (safe_create_leading_directories_const(new_git_dir) < 0)
  		die(_("could not create directory '%s'"), new_git_dir);
  	real_new_git_dir = real_pathdup(new_git_dir, 1);
  
  	fprintf(stderr, _("Migrating git directory of '%s%s' from\n'%s' to\n'%s'\n"),
  		get_super_prefix_or_empty(), path,
  		real_old_git_dir, real_new_git_dir);
  
  	relocate_gitdir(path, real_old_git_dir, real_new_git_dir);
  
  	free(old_git_dir);
  	free(real_old_git_dir);
  	free(real_new_git_dir);
  }
  
  /*
   * Migrate the git directory of the submodule given by path from
   * having its git directory within the working tree to the git dir nested
   * in its superprojects git dir under modules/.
   */
  void absorb_git_dir_into_superproject(const char *path,
  				      unsigned flags)
  {
  	int err_code;
  	const char *sub_git_dir;
  	struct strbuf gitdir = STRBUF_INIT;
  	strbuf_addf(&gitdir, "%s/.git", path);
  	sub_git_dir = resolve_gitdir_gently(gitdir.buf, &err_code);
  
  	/* Not populated? */
  	if (!sub_git_dir) {
  		const struct submodule *sub;
  
  		if (err_code == READ_GITFILE_ERR_STAT_FAILED) {
  			/* unpopulated as expected */
  			strbuf_release(&gitdir);
  			return;
  		}
  
  		if (err_code != READ_GITFILE_ERR_NOT_A_REPO)
  			/* We don't know what broke here. */
  			read_gitfile_error_die(err_code, path, NULL);
  
  		/*
  		* Maybe populated, but no git directory was found?
  		* This can happen if the superproject is a submodule
  		* itself and was just absorbed. The absorption of the
  		* superproject did not rewrite the git file links yet,
  		* fix it now.
  		*/
  		sub = submodule_from_path(the_repository, &null_oid, path);
  		if (!sub)
  			die(_("could not lookup name for submodule '%s'"), path);
  		connect_work_tree_and_git_dir(path,
  			git_path("modules/%s", sub->name), 0);
  	} else {
  		/* Is it already absorbed into the superprojects git dir? */
  		char *real_sub_git_dir = real_pathdup(sub_git_dir, 1);
  		char *real_common_git_dir = real_pathdup(get_git_common_dir(), 1);
  
  		if (!starts_with(real_sub_git_dir, real_common_git_dir))
  			relocate_single_git_dir_into_superproject(path);
  
  		free(real_sub_git_dir);
  		free(real_common_git_dir);
  	}
  	strbuf_release(&gitdir);
  
  	if (flags & ABSORB_GITDIR_RECURSE_SUBMODULES) {
  		struct child_process cp = CHILD_PROCESS_INIT;
  		struct strbuf sb = STRBUF_INIT;
  
  		if (flags & ~ABSORB_GITDIR_RECURSE_SUBMODULES)
  			BUG("we don't know how to pass the flags down?");
  
  		strbuf_addstr(&sb, get_super_prefix_or_empty());
  		strbuf_addstr(&sb, path);
  		strbuf_addch(&sb, '/');
  
  		cp.dir = path;
  		cp.git_cmd = 1;
  		cp.no_stdin = 1;
  		argv_array_pushl(&cp.args, "--super-prefix", sb.buf,
  					   "submodule--helper",
  					   "absorb-git-dirs", NULL);
  		prepare_submodule_repo_env(&cp.env_array);
  		if (run_command(&cp))
  			die(_("could not recurse into submodule '%s'"), path);
  
  		strbuf_release(&sb);
  	}
  }
  
  const char *get_superproject_working_tree(void)
  {
  	struct child_process cp = CHILD_PROCESS_INIT;
  	struct strbuf sb = STRBUF_INIT;
  	const char *one_up = real_path_if_valid("../");
  	const char *cwd = xgetcwd();
  	const char *ret = NULL;
  	const char *subpath;
  	int code;
  	ssize_t len;
  
  	if (!is_inside_work_tree())
  		/*
  		 * FIXME:
  		 * We might have a superproject, but it is harder
  		 * to determine.
  		 */
  		return NULL;
  
  	if (!one_up)
  		return NULL;
  
  	subpath = relative_path(cwd, one_up, &sb);
  
  	prepare_submodule_repo_env(&cp.env_array);
  	argv_array_pop(&cp.env_array);
  
  	argv_array_pushl(&cp.args, "--literal-pathspecs", "-C", "..",
  			"ls-files", "-z", "--stage", "--full-name", "--",
  			subpath, NULL);
  	strbuf_reset(&sb);
  
  	cp.no_stdin = 1;
  	cp.no_stderr = 1;
  	cp.out = -1;
  	cp.git_cmd = 1;
  
  	if (start_command(&cp))
  		die(_("could not start ls-files in .."));
  
  	len = strbuf_read(&sb, cp.out, PATH_MAX);
  	close(cp.out);
  
  	if (starts_with(sb.buf, "160000")) {
  		int super_sub_len;
  		int cwd_len = strlen(cwd);
  		char *super_sub, *super_wt;
  
  		/*
  		 * There is a superproject having this repo as a submodule.
  		 * The format is <mode> SP <hash> SP <stage> TAB <full name> \0,
  		 * We're only interested in the name after the tab.
  		 */
  		super_sub = strchr(sb.buf, '\t') + 1;
  		super_sub_len = strlen(super_sub);
  
  		if (super_sub_len > cwd_len ||
  		    strcmp(&cwd[cwd_len - super_sub_len], super_sub))
  			BUG("returned path string doesn't match cwd?");
  
  		super_wt = xstrdup(cwd);
  		super_wt[cwd_len - super_sub_len] = '\0';
  
  		ret = real_path(super_wt);
  		free(super_wt);
  	}
  	strbuf_release(&sb);
  
  	code = finish_command(&cp);
  
  	if (code == 128)
  		/* '../' is not a git repository */
  		return NULL;
  	if (code == 0 && len == 0)
  		/* There is an unrelated git repository at '../' */
  		return NULL;
  	if (code)
  		die(_("ls-tree returned unexpected return code %d"), code);
  
  	return ret;
  }
  
  /*
   * Put the gitdir for a submodule (given relative to the main
   * repository worktree) into `buf`, or return -1 on error.
   */
  int submodule_to_gitdir(struct strbuf *buf, const char *submodule)
  {
  	const struct submodule *sub;
  	const char *git_dir;
  	int ret = 0;
  
  	strbuf_reset(buf);
  	strbuf_addstr(buf, submodule);
  	strbuf_complete(buf, '/');
  	strbuf_addstr(buf, ".git");
  
  	git_dir = read_gitfile(buf->buf);
  	if (git_dir) {
  		strbuf_reset(buf);
  		strbuf_addstr(buf, git_dir);
  	}
  	if (!is_git_directory(buf->buf)) {
  		sub = submodule_from_path(the_repository, &null_oid, submodule);
  		if (!sub) {
  			ret = -1;
  			goto cleanup;
  		}
  		strbuf_reset(buf);
  		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
  	}
  
  cleanup:
  	return ret;
  }
  