diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index f903683189..6cdd9d43c5 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -186,15 +186,23 @@ endif::git-pull[]
 ifndef::git-pull[]
 --recurse-submodules[=yes|on-demand|no]::
 	This option controls if and under what conditions new commits of
-	populated submodules should be fetched too. It can be used as a
-	boolean option to completely disable recursion when set to 'no' or to
-	unconditionally recurse into all populated submodules when set to
-	'yes', which is the default when this option is used without any
-	value. Use 'on-demand' to only recurse into a populated submodule
-	when the superproject retrieves a commit that updates the submodule's
-	reference to a commit that isn't already in the local submodule
-	clone. By default, 'on-demand' is used, unless
-	`fetch.recurseSubmodules` is set (see linkgit:git-config[1]).
+	submodules should be fetched too. When recursing through submodules,
+	`git fetch` always attempts to fetch "changed" submodules, that is, a
+	submodule that has commits that are referenced by a newly fetched
+	superproject commit but are missing in the local submodule clone. A
+	changed submodule can be fetched as long as it is present locally e.g.
+	in `$GIT_DIR/modules/` (see linkgit:gitsubmodules[7]); if the upstream
+	adds a new submodule, that submodule cannot be fetched until it is
+	cloned e.g. by `git submodule update`.
++
+When set to 'on-demand', only changed submodules are fetched. When set
+to 'yes', all populated submodules are fetched and submodules that are
+both unpopulated and changed are fetched. When set to 'no', submodules
+are never fetched.
++
+When unspecified, this uses the value of `fetch.recurseSubmodules` if it
+is set (see linkgit:git-config[1]), defaulting to 'on-demand' if unset.
+When this option is used without any value, it defaults to 'yes'.
 endif::git-pull[]
 
 -j::
diff --git a/Documentation/git-fetch.txt b/Documentation/git-fetch.txt
index 550c16ca61..e9d364669a 100644
--- a/Documentation/git-fetch.txt
+++ b/Documentation/git-fetch.txt
@@ -287,12 +287,10 @@ include::transfer-data-leaks.txt[]
 
 BUGS
 ----
-Using --recurse-submodules can only fetch new commits in already checked
-out submodules right now. When e.g. upstream added a new submodule in the
-just fetched commits of the superproject the submodule itself cannot be
-fetched, making it impossible to check out that submodule later without
-having to do a fetch again. This is expected to be fixed in a future Git
-version.
+Using --recurse-submodules can only fetch new commits in submodules that are
+present locally e.g. in `$GIT_DIR/modules/`. If the upstream adds a new
+submodule, that submodule cannot be fetched until it is cloned e.g. by `git
+submodule update`. This is expected to be fixed in a future Git version.
 
 SEE ALSO
 --------
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 4d12c2fd4d..9b4018f62c 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -2258,13 +2258,13 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 			max_children = fetch_parallel_config;
 
 		add_options_to_argv(&options);
-		result = fetch_populated_submodules(the_repository,
-						    &options,
-						    submodule_prefix,
-						    recurse_submodules,
-						    recurse_submodules_default,
-						    verbosity < 0,
-						    max_children);
+		result = fetch_submodules(the_repository,
+					  &options,
+					  submodule_prefix,
+					  recurse_submodules,
+					  recurse_submodules_default,
+					  verbosity < 0,
+					  max_children);
 		strvec_clear(&options);
 	}
 
diff --git a/submodule.c b/submodule.c
index 5ace18a7d9..93c78a4dc3 100644
--- a/submodule.c
+++ b/submodule.c
@@ -167,26 +167,6 @@ void stage_updated_gitmodules(struct index_state *istate)
 
 static struct string_list added_submodule_odb_paths = STRING_LIST_INIT_NODUP;
 
-/* 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;
-	}
-	string_list_insert(&added_submodule_odb_paths,
-			   strbuf_detach(&objects_directory, NULL));
-done:
-	strbuf_release(&objects_directory);
-	return ret;
-}
-
 void add_submodule_odb_by_path(const char *path)
 {
 	string_list_insert(&added_submodule_odb_paths, xstrdup(path));
@@ -782,19 +762,6 @@ const struct submodule *submodule_from_ce(const struct cache_entry *ce)
 	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;
@@ -819,6 +786,52 @@ static const char *default_name_or_path(const char *path_or_name)
 	return path_or_name;
 }
 
+/*
+ * Holds relevant information for a changed submodule. Used as the .util
+ * member of the changed submodule name string_list_item.
+ *
+ * (super_oid, path) allows the submodule config to be read from _some_
+ * .gitmodules file. We store this information the first time we find a
+ * superproject commit that points to the submodule, but this is
+ * arbitrary - we can choose any (super_oid, path) that matches the
+ * submodule's name.
+ *
+ * NEEDSWORK: Storing an arbitrary commit is undesirable because we can't
+ * guarantee that we're reading the commit that the user would expect. A better
+ * scheme would be to just fetch a submodule by its name. This requires two
+ * steps:
+ * - Create a function that behaves like repo_submodule_init(), but accepts a
+ *   submodule name instead of treeish_name and path. This should be easy
+ *   because repo_submodule_init() internally uses the submodule's name.
+ *
+ * - Replace most instances of 'struct submodule' (which is the .gitmodules
+ *   config) with just the submodule name. This is OK because we expect
+ *   submodule settings to be stored in .git/config (via "git submodule init"),
+ *   not .gitmodules. This also lets us delete get_non_gitmodules_submodule(),
+ *   which constructs a bogus 'struct submodule' for the sake of giving a
+ *   placeholder name to a gitlink.
+ */
+struct changed_submodule_data {
+	/*
+	 * The first superproject commit in the rev walk that points to
+	 * the submodule.
+	 */
+	const struct object_id *super_oid;
+	/*
+	 * Path to the submodule in the superproject commit referenced
+	 * by 'super_oid'.
+	 */
+	char *path;
+	/* The submodule commits that have changed in the rev walk. */
+	struct oid_array new_commits;
+};
+
+static void changed_submodule_data_clear(struct changed_submodule_data *cs_data)
+{
+	oid_array_clear(&cs_data->new_commits);
+	free(cs_data->path);
+}
+
 static void collect_changed_submodules_cb(struct diff_queue_struct *q,
 					  struct diff_options *options,
 					  void *data)
@@ -830,9 +843,10 @@ static void collect_changed_submodules_cb(struct diff_queue_struct *q,
 
 	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;
+		struct string_list_item *item;
+		struct changed_submodule_data *cs_data;
 
 		if (!S_ISGITLINK(p->two->mode))
 			continue;
@@ -859,8 +873,16 @@ static void collect_changed_submodules_cb(struct diff_queue_struct *q,
 		if (!name)
 			continue;
 
-		commits = submodule_commits(changed, name);
-		oid_array_append(commits, &p->two->oid);
+		item = string_list_insert(changed, name);
+		if (item->util)
+			cs_data = item->util;
+		else {
+			item->util = xcalloc(1, sizeof(struct changed_submodule_data));
+			cs_data = item->util;
+			cs_data->super_oid = commit_oid;
+			cs_data->path = xstrdup(p->two->path);
+		}
+		oid_array_append(&cs_data->new_commits, &p->two->oid);
 	}
 }
 
@@ -907,11 +929,12 @@ static void collect_changed_submodules(struct repository *r,
 	reset_revision_walk();
 }
 
-static void free_submodules_oids(struct string_list *submodules)
+static void free_submodules_data(struct string_list *submodules)
 {
 	struct string_list_item *item;
 	for_each_string_list_item(item, submodules)
-		oid_array_clear((struct oid_array *) item->util);
+		changed_submodule_data_clear(item->util);
+
 	string_list_clear(submodules, 1);
 }
 
@@ -932,6 +955,7 @@ struct has_commit_data {
 	struct repository *repo;
 	int result;
 	const char *path;
+	const struct object_id *super_oid;
 };
 
 static int check_has_commit(const struct object_id *oid, void *data)
@@ -940,9 +964,10 @@ static int check_has_commit(const struct object_id *oid, void *data)
 	struct repository subrepo;
 	enum object_type type;
 
-	if (repo_submodule_init(&subrepo, cb->repo, cb->path, null_oid())) {
+	if (repo_submodule_init(&subrepo, cb->repo, cb->path, cb->super_oid)) {
 		cb->result = 0;
-		goto cleanup;
+		/* subrepo failed to init, so don't clean it up. */
+		return 0;
 	}
 
 	type = oid_object_info(&subrepo, oid, NULL);
@@ -968,21 +993,15 @@ static int check_has_commit(const struct object_id *oid, void *data)
 
 static int submodule_has_commits(struct repository *r,
 				 const char *path,
+				 const struct object_id *super_oid,
 				 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;
+	struct has_commit_data has_commit = {
+		.repo = r,
+		.result = 1,
+		.path = path,
+		.super_oid = super_oid
+	};
 
 	oid_array_for_each_unique(commits, check_has_commit, &has_commit);
 
@@ -1017,7 +1036,7 @@ static int submodule_needs_pushing(struct repository *r,
 				   const char *path,
 				   struct oid_array *commits)
 {
-	if (!submodule_has_commits(r, path, commits))
+	if (!submodule_has_commits(r, path, null_oid(), commits))
 		/*
 		 * NOTE: We do consider it safe to return "no" here. The
 		 * correct answer would be "We do not know" instead of
@@ -1077,7 +1096,7 @@ int find_unpushed_submodules(struct repository *r,
 	collect_changed_submodules(r, &submodules, &argv);
 
 	for_each_string_list_item(name, &submodules) {
-		struct oid_array *commits = name->util;
+		struct changed_submodule_data *cs_data = name->util;
 		const struct submodule *submodule;
 		const char *path = NULL;
 
@@ -1090,11 +1109,11 @@ int find_unpushed_submodules(struct repository *r,
 		if (!path)
 			continue;
 
-		if (submodule_needs_pushing(r, path, commits))
+		if (submodule_needs_pushing(r, path, &cs_data->new_commits))
 			string_list_insert(needs_pushing, path);
 	}
 
-	free_submodules_oids(&submodules);
+	free_submodules_data(&submodules);
 	strvec_clear(&argv);
 
 	return needs_pushing->nr;
@@ -1240,14 +1259,36 @@ void check_for_new_submodule_commits(struct object_id *oid)
 	oid_array_append(&ref_tips_after_fetch, oid);
 }
 
+/*
+ * Returns 1 if there is at least one submodule gitdir in
+ * $GIT_DIR/modules and 0 otherwise. This follows
+ * submodule_name_to_gitdir(), which looks for submodules in
+ * $GIT_DIR/modules, not $GIT_COMMON_DIR.
+ *
+ * A submodule can be moved to $GIT_DIR/modules manually by running "git
+ * submodule absorbgitdirs", or it may be initialized there by "git
+ * submodule update".
+ */
+static int repo_has_absorbed_submodules(struct repository *r)
+{
+	int ret;
+	struct strbuf buf = STRBUF_INIT;
+
+	strbuf_repo_git_path(&buf, r, "modules/");
+	ret = file_exists(buf.buf) && !is_empty_dir(buf.buf);
+	strbuf_release(&buf);
+	return ret;
+}
+
 static void calculate_changed_submodule_paths(struct repository *r,
 		struct string_list *changed_submodule_names)
 {
 	struct strvec argv = STRVEC_INIT;
 	struct string_list_item *name;
 
-	/* No need to check if there are no submodules configured */
-	if (!submodule_from_path(r, NULL, NULL))
+	/* No need to check if no submodules would be fetched */
+	if (!submodule_from_path(r, NULL, NULL) &&
+	    !repo_has_absorbed_submodules(r))
 		return;
 
 	strvec_push(&argv, "--"); /* argv[0] program name */
@@ -1264,7 +1305,7 @@ static void calculate_changed_submodule_paths(struct repository *r,
 	collect_changed_submodules(r, changed_submodule_names, &argv);
 
 	for_each_string_list_item(name, changed_submodule_names) {
-		struct oid_array *commits = name->util;
+		struct changed_submodule_data *cs_data = name->util;
 		const struct submodule *submodule;
 		const char *path = NULL;
 
@@ -1277,8 +1318,8 @@ static void calculate_changed_submodule_paths(struct repository *r,
 		if (!path)
 			continue;
 
-		if (submodule_has_commits(r, path, commits)) {
-			oid_array_clear(commits);
+		if (submodule_has_commits(r, path, null_oid(), &cs_data->new_commits)) {
+			changed_submodule_data_clear(cs_data);
 			*name->string = '\0';
 		}
 	}
@@ -1315,12 +1356,21 @@ int submodule_touches_in_range(struct repository *r,
 
 	strvec_clear(&args);
 
-	free_submodules_oids(&subs);
+	free_submodules_data(&subs);
 	return ret;
 }
 
 struct submodule_parallel_fetch {
-	int count;
+	/*
+	 * The index of the last index entry processed by
+	 * get_fetch_task_from_index().
+	 */
+	int index_count;
+	/*
+	 * The index of the last string_list entry processed by
+	 * get_fetch_task_from_changed().
+	 */
+	int changed_count;
 	struct strvec args;
 	struct repository *r;
 	const char *prefix;
@@ -1329,7 +1379,16 @@ struct submodule_parallel_fetch {
 	int quiet;
 	int result;
 
+	/*
+	 * Names of submodules that have new commits. Generated by
+	 * walking the newly fetched superproject commits.
+	 */
 	struct string_list changed_submodule_names;
+	/*
+	 * Names of submodules that have already been processed. Lets us
+	 * avoid fetching the same submodule more than once.
+	 */
+	struct string_list seen_submodule_names;
 
 	/* Pending fetches by OIDs */
 	struct fetch_task **oid_fetch_tasks;
@@ -1340,6 +1399,7 @@ struct submodule_parallel_fetch {
 #define SPF_INIT { \
 	.args = STRVEC_INIT, \
 	.changed_submodule_names = STRING_LIST_INIT_DUP, \
+	.seen_submodule_names = STRING_LIST_INIT_DUP, \
 	.submodules_with_errors = STRBUF_INIT, \
 }
 
@@ -1376,6 +1436,8 @@ struct fetch_task {
 	struct repository *repo;
 	const struct submodule *sub;
 	unsigned free_sub : 1; /* Do we need to free the submodule? */
+	const char *default_argv; /* The default fetch mode. */
+	struct strvec git_args; /* Args for the child git process. */
 
 	struct oid_array *commits; /* Ensure these commits are fetched */
 };
@@ -1401,31 +1463,6 @@ static const struct submodule *get_non_gitmodules_submodule(const char *path)
 	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)
@@ -1436,14 +1473,17 @@ static void fetch_task_release(struct fetch_task *p)
 	if (p->repo)
 		repo_clear(p->repo);
 	FREE_AND_NULL(p->repo);
+
+	strvec_clear(&p->git_args);
 }
 
 static struct repository *get_submodule_repo_for(struct repository *r,
-						 const char *path)
+						 const char *path,
+						 const struct object_id *treeish_name)
 {
 	struct repository *ret = xmalloc(sizeof(*ret));
 
-	if (repo_submodule_init(ret, r, path, null_oid())) {
+	if (repo_submodule_init(ret, r, path, treeish_name)) {
 		free(ret);
 		return NULL;
 	}
@@ -1451,67 +1491,83 @@ static struct repository *get_submodule_repo_for(struct repository *r,
 	return ret;
 }
 
-static int get_next_submodule(struct child_process *cp,
-			      struct strbuf *err, void *data, void **task_cb)
+static struct fetch_task *fetch_task_create(struct submodule_parallel_fetch *spf,
+					    const char *path,
+					    const struct object_id *treeish_name)
 {
-	struct submodule_parallel_fetch *spf = data;
+	struct fetch_task *task = xmalloc(sizeof(*task));
+	memset(task, 0, sizeof(*task));
 
-	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;
+	task->sub = submodule_from_path(spf->r, treeish_name, 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)
+			goto cleanup;
+
+		task->free_sub = 1;
+	}
+
+	if (string_list_lookup(&spf->seen_submodule_names, task->sub->name))
+		goto cleanup;
+
+	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))
+			goto cleanup;
+		task->default_argv = "on-demand";
+		break;
+	case RECURSE_SUBMODULES_ON:
+		task->default_argv = "yes";
+		break;
+	case RECURSE_SUBMODULES_OFF:
+		goto cleanup;
+	}
+
+	task->repo = get_submodule_repo_for(spf->r, path, treeish_name);
+
+	return task;
+
+ cleanup:
+	fetch_task_release(task);
+	free(task);
+	return NULL;
+}
+
+static struct fetch_task *
+get_fetch_task_from_index(struct submodule_parallel_fetch *spf,
+			  struct strbuf *err)
+{
+	for (; spf->index_count < spf->r->index->cache_nr; spf->index_count++) {
+		const struct cache_entry *ce =
+			spf->r->index->cache[spf->index_count];
 		struct fetch_task *task;
 
 		if (!S_ISGITLINK(ce->ce_mode))
 			continue;
 
-		task = fetch_task_create(spf->r, ce->name);
+		task = fetch_task_create(spf, ce->name, null_oid());
 		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->path);
 		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);
-			strvec_init(&cp->args);
-			strvec_pushv(&cp->args, spf->args.v);
-			strvec_push(&cp->args, default_argv);
-			strvec_push(&cp->args, "--submodule-prefix");
 
-			strbuf_addf(&submodule_prefix, "%s%s/",
-						       spf->prefix,
-						       task->sub->path);
-			strvec_push(&cp->args, submodule_prefix.buf);
-
-			spf->count++;
-			*task_cb = task;
-
-			strbuf_release(&submodule_prefix);
-			return 1;
+			spf->index_count++;
+			return task;
 		} else {
 			struct strbuf empty_submodule_path = STRBUF_INIT;
 
@@ -1535,6 +1591,111 @@ static int get_next_submodule(struct child_process *cp,
 			strbuf_release(&empty_submodule_path);
 		}
 	}
+	return NULL;
+}
+
+static struct fetch_task *
+get_fetch_task_from_changed(struct submodule_parallel_fetch *spf,
+			    struct strbuf *err)
+{
+	for (; spf->changed_count < spf->changed_submodule_names.nr;
+	     spf->changed_count++) {
+		struct string_list_item item =
+			spf->changed_submodule_names.items[spf->changed_count];
+		struct changed_submodule_data *cs_data = item.util;
+		struct fetch_task *task;
+
+		if (!is_tree_submodule_active(spf->r, cs_data->super_oid,cs_data->path))
+			continue;
+
+		task = fetch_task_create(spf, cs_data->path,
+					 cs_data->super_oid);
+		if (!task)
+			continue;
+
+		if (!task->repo) {
+			strbuf_addf(err, _("Could not access submodule '%s' at commit %s\n"),
+				    cs_data->path,
+				    find_unique_abbrev(cs_data->super_oid, DEFAULT_ABBREV));
+
+			fetch_task_release(task);
+			free(task);
+			continue;
+		}
+
+		if (!spf->quiet)
+			strbuf_addf(err,
+				    _("Fetching submodule %s%s at commit %s\n"),
+				    spf->prefix, task->sub->path,
+				    find_unique_abbrev(cs_data->super_oid,
+						       DEFAULT_ABBREV));
+
+		spf->changed_count++;
+		/*
+		 * NEEDSWORK: Submodules set/unset a value for
+		 * core.worktree when they are populated/unpopulated by
+		 * "git checkout" (and similar commands, see
+		 * submodule_move_head() and
+		 * connect_work_tree_and_git_dir()), but if the
+		 * submodule is unpopulated in another way (e.g. "git
+		 * rm", "rm -r"), core.worktree will still be set even
+		 * though the directory doesn't exist, and the child
+		 * process will crash while trying to chdir into the
+		 * nonexistent directory.
+		 *
+		 * In this case, we know that the submodule has no
+		 * working tree, so we can work around this by
+		 * setting "--work-tree=." (--bare does not work because
+		 * worktree settings take precedence over bare-ness).
+		 * However, this is not necessarily true in other cases,
+		 * so a generalized solution is still necessary.
+		 *
+		 * Possible solutions:
+		 * - teach "git [add|rm]" to unset core.worktree and
+		 *   discourage users from removing submodules without
+		 *   using a Git command.
+		 * - teach submodule child processes to ignore stale
+		 *   core.worktree values.
+		 */
+		strvec_push(&task->git_args, "--work-tree=.");
+		return task;
+	}
+	return NULL;
+}
+
+static int get_next_submodule(struct child_process *cp, struct strbuf *err,
+			      void *data, void **task_cb)
+{
+	struct submodule_parallel_fetch *spf = data;
+	struct fetch_task *task =
+		get_fetch_task_from_index(spf, err);
+	if (!task)
+		task = get_fetch_task_from_changed(spf, err);
+
+	if (task) {
+		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;
+		strvec_init(&cp->args);
+		if (task->git_args.nr)
+			strvec_pushv(&cp->args, task->git_args.v);
+		strvec_pushv(&cp->args, spf->args.v);
+		strvec_push(&cp->args, task->default_argv);
+		strvec_push(&cp->args, "--submodule-prefix");
+
+		strbuf_addf(&submodule_prefix, "%s%s/",
+						spf->prefix,
+						task->sub->path);
+		strvec_push(&cp->args, submodule_prefix.buf);
+		*task_cb = task;
+
+		strbuf_release(&submodule_prefix);
+		string_list_insert(&spf->seen_submodule_names, task->sub->name);
+		return 1;
+	}
 
 	if (spf->oid_fetch_tasks_nr) {
 		struct fetch_task *task =
@@ -1597,7 +1758,7 @@ static int fetch_finish(int retvalue, struct strbuf *err,
 	struct fetch_task *task = task_cb;
 
 	struct string_list_item *it;
-	struct oid_array *commits;
+	struct changed_submodule_data *cs_data;
 
 	if (!task || !task->sub)
 		BUG("callback cookie bogus");
@@ -1625,14 +1786,14 @@ static int fetch_finish(int retvalue, struct strbuf *err,
 		/* Could be an unchanged submodule, not contained in the list */
 		goto out;
 
-	commits = it->util;
-	oid_array_filter(commits,
+	cs_data = it->util;
+	oid_array_filter(&cs_data->new_commits,
 			 commit_missing_in_sub,
 			 task->repo);
 
 	/* Are there commits we want, but do not exist? */
-	if (commits->nr) {
-		task->commits = commits;
+	if (cs_data->new_commits.nr) {
+		task->commits = &cs_data->new_commits;
 		ALLOC_GROW(spf->oid_fetch_tasks,
 			   spf->oid_fetch_tasks_nr + 1,
 			   spf->oid_fetch_tasks_alloc);
@@ -1647,11 +1808,11 @@ static int fetch_finish(int retvalue, struct strbuf *err,
 	return 0;
 }
 
-int fetch_populated_submodules(struct repository *r,
-			       const struct strvec *options,
-			       const char *prefix, int command_line_option,
-			       int default_option,
-			       int quiet, int max_parallel_jobs)
+int fetch_submodules(struct repository *r,
+		     const struct strvec *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;
@@ -1690,7 +1851,7 @@ int fetch_populated_submodules(struct repository *r,
 
 	strvec_clear(&spf.args);
 out:
-	free_submodules_oids(&spf.changed_submodule_names);
+	free_submodules_data(&spf.changed_submodule_names);
 	return spf.result;
 }
 
diff --git a/submodule.h b/submodule.h
index 784ceffc0e..40c1445237 100644
--- a/submodule.h
+++ b/submodule.h
@@ -88,12 +88,12 @@ int should_update_submodules(void);
  */
 const struct submodule *submodule_from_ce(const struct cache_entry *ce);
 void check_for_new_submodule_commits(struct object_id *oid);
-int fetch_populated_submodules(struct repository *r,
-			       const struct strvec *options,
-			       const char *prefix,
-			       int command_line_option,
-			       int default_option,
-			       int quiet, int max_parallel_jobs);
+int fetch_submodules(struct repository *r,
+		     const struct strvec *options,
+		     const char *prefix,
+		     int command_line_option,
+		     int default_option,
+		     int quiet, int max_parallel_jobs);
 unsigned is_submodule_modified(const char *path, int ignore_untracked);
 int submodule_uses_gitfile(const char *path);
 
@@ -103,12 +103,11 @@ int submodule_uses_gitfile(const char *path);
 int bad_to_remove_submodule(const char *path, unsigned flags);
 
 /*
- * Call add_submodule_odb() to add the submodule at the given path to a list.
- * When register_all_submodule_odb_as_alternates() is called, the object stores
- * of all submodules in that list will be added as alternates in
- * the_repository.
+ * Call add_submodule_odb_by_path() to add the submodule at the given
+ * path to a list. When register_all_submodule_odb_as_alternates() is
+ * called, the object stores of all submodules in that list will be
+ * added as alternates in the_repository.
  */
-int add_submodule_odb(const char *path);
 void add_submodule_odb_by_path(const char *path);
 int register_all_submodule_odb_as_alternates(void);
 
diff --git a/t/t5526-fetch-submodules.sh b/t/t5526-fetch-submodules.sh
index 840c89cc8b..43dada8544 100755
--- a/t/t5526-fetch-submodules.sh
+++ b/t/t5526-fetch-submodules.sh
@@ -10,33 +10,122 @@ export GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB
 
 pwd=$(pwd)
 
-add_upstream_commit() {
+write_expected_sub () {
+	NEW_HEAD=$1 &&
+	SUPER_HEAD=$2 &&
+	cat >"$pwd/expect.err.sub" <<-EOF
+	Fetching submodule submodule${SUPER_HEAD:+ at commit $SUPER_HEAD}
+	From $pwd/submodule
+	   OLD_HEAD..$NEW_HEAD  sub        -> origin/sub
+	EOF
+}
+
+write_expected_sub2 () {
+	NEW_HEAD=$1 &&
+	SUPER_HEAD=$2 &&
+	cat >"$pwd/expect.err.sub2" <<-EOF
+	Fetching submodule submodule2${SUPER_HEAD:+ at commit $SUPER_HEAD}
+	From $pwd/submodule2
+	   OLD_HEAD..$NEW_HEAD  sub2       -> origin/sub2
+	EOF
+}
+
+write_expected_deep () {
+	NEW_HEAD=$1 &&
+	SUB_HEAD=$2 &&
+	cat >"$pwd/expect.err.deep" <<-EOF
+	Fetching submodule submodule/subdir/deepsubmodule${SUB_HEAD:+ at commit $SUB_HEAD}
+	From $pwd/deepsubmodule
+	   OLD_HEAD..$NEW_HEAD  deep       -> origin/deep
+	EOF
+}
+
+write_expected_super () {
+	NEW_HEAD=$1 &&
+	cat >"$pwd/expect.err.super" <<-EOF
+	From $pwd/.
+	   OLD_HEAD..$NEW_HEAD  super      -> origin/super
+	EOF
+}
+
+# For each submodule in the test setup, this creates a commit and writes
+# a file that contains the expected err if that new commit were fetched.
+# These output files get concatenated in the right order by
+# verify_fetch_result().
+add_submodule_commits () {
 	(
 		cd submodule &&
-		head1=$(git rev-parse --short HEAD) &&
 		echo new >> subfile &&
 		test_tick &&
 		git add subfile &&
 		git commit -m new subfile &&
-		head2=$(git rev-parse --short HEAD) &&
-		echo "Fetching submodule submodule" > ../expect.err &&
-		echo "From $pwd/submodule" >> ../expect.err &&
-		echo "   $head1..$head2  sub        -> origin/sub" >> ../expect.err
+		new_head=$(git rev-parse --short HEAD) &&
+		write_expected_sub $new_head
 	) &&
 	(
 		cd deepsubmodule &&
-		head1=$(git rev-parse --short HEAD) &&
 		echo new >> deepsubfile &&
 		test_tick &&
 		git add deepsubfile &&
 		git commit -m new deepsubfile &&
-		head2=$(git rev-parse --short HEAD) &&
-		echo "Fetching submodule submodule/subdir/deepsubmodule" >> ../expect.err
-		echo "From $pwd/deepsubmodule" >> ../expect.err &&
-		echo "   $head1..$head2  deep       -> origin/deep" >> ../expect.err
+		new_head=$(git rev-parse --short HEAD) &&
+		write_expected_deep $new_head
 	)
 }
 
+# For each superproject in the test setup, update its submodule, add the
+# submodule and create a new commit with the submodule change.
+#
+# This requires add_submodule_commits() to be called first, otherwise
+# the submodules will not have changed and cannot be "git add"-ed.
+add_superproject_commits () {
+	(
+		cd submodule &&
+		(
+			cd subdir/deepsubmodule &&
+			git fetch &&
+			git checkout -q FETCH_HEAD
+		) &&
+		git add subdir/deepsubmodule &&
+		git commit -m "new deep submodule"
+	) &&
+	git add submodule &&
+	git commit -m "new submodule" &&
+	super_head=$(git rev-parse --short HEAD) &&
+	sub_head=$(git -C submodule rev-parse --short HEAD) &&
+	write_expected_super $super_head &&
+	write_expected_sub $sub_head
+}
+
+# Verifies that the expected repositories were fetched. This is done by
+# concatenating the files expect.err.[super|sub|deep] in the correct
+# order and comparing it to the actual stderr.
+#
+# If a repo should not be fetched in the test, its corresponding
+# expect.err file should be rm-ed.
+verify_fetch_result () {
+	ACTUAL_ERR=$1 &&
+	rm -f expect.err.combined &&
+	if test -f expect.err.super
+	then
+		cat expect.err.super >>expect.err.combined
+	fi &&
+	if test -f expect.err.sub
+	then
+		cat expect.err.sub >>expect.err.combined
+	fi &&
+	if test -f expect.err.deep
+	then
+		cat expect.err.deep >>expect.err.combined
+	fi &&
+	if test -f expect.err.sub2
+	then
+		cat expect.err.sub2 >>expect.err.combined
+	fi &&
+	sed -e 's/[0-9a-f][0-9a-f]*\.\./OLD_HEAD\.\./' "$ACTUAL_ERR" >actual.err.cmp &&
+	test_cmp expect.err.combined actual.err.cmp
+}
+
 test_expect_success setup '
 	mkdir deepsubmodule &&
 	(
@@ -68,38 +157,38 @@ test_expect_success setup '
 '
 
 test_expect_success "fetch --recurse-submodules recurses into submodules" '
-	add_upstream_commit &&
+	add_submodule_commits &&
 	(
 		cd downstream &&
 		git fetch --recurse-submodules >../actual.out 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "submodule.recurse option triggers recursive fetch" '
-	add_upstream_commit &&
+	add_submodule_commits &&
 	(
 		cd downstream &&
 		git -c submodule.recurse fetch >../actual.out 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "fetch --recurse-submodules -j2 has the same output behaviour" '
-	add_upstream_commit &&
+	add_submodule_commits &&
 	(
 		cd downstream &&
 		GIT_TRACE="$TRASH_DIRECTORY/trace.out" git fetch --recurse-submodules -j2 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err &&
+	verify_fetch_result actual.err &&
 	grep "2 tasks" trace.out
 '
 
 test_expect_success "fetch alone only fetches superproject" '
-	add_upstream_commit &&
+	add_submodule_commits &&
 	(
 		cd downstream &&
 		git fetch >../actual.out 2>../actual.err
@@ -124,11 +213,11 @@ test_expect_success "using fetchRecurseSubmodules=true in .gitmodules recurses i
 		git fetch >../actual.out 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "--no-recurse-submodules overrides .gitmodules config" '
-	add_upstream_commit &&
+	add_submodule_commits &&
 	(
 		cd downstream &&
 		git fetch --no-recurse-submodules >../actual.out 2>../actual.err
@@ -155,7 +244,7 @@ test_expect_success "--recurse-submodules overrides fetchRecurseSubmodules setti
 		git config --unset submodule.submodule.fetchRecurseSubmodules
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "--quiet propagates to submodules" '
@@ -177,13 +266,13 @@ test_expect_success "--quiet propagates to parallel submodules" '
 '
 
 test_expect_success "--dry-run propagates to submodules" '
-	add_upstream_commit &&
+	add_submodule_commits &&
 	(
 		cd downstream &&
 		git fetch --recurse-submodules --dry-run >../actual.out 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "Without --dry-run propagates to submodules" '
@@ -192,22 +281,22 @@ test_expect_success "Without --dry-run propagates to submodules" '
 		git fetch --recurse-submodules >../actual.out 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "recurseSubmodules=true propagates into submodules" '
-	add_upstream_commit &&
+	add_submodule_commits &&
 	(
 		cd downstream &&
 		git config fetch.recurseSubmodules true &&
 		git fetch >../actual.out 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "--recurse-submodules overrides config in submodule" '
-	add_upstream_commit &&
+	add_submodule_commits &&
 	(
 		cd downstream &&
 		(
@@ -217,11 +306,11 @@ test_expect_success "--recurse-submodules overrides config in submodule" '
 		git fetch --recurse-submodules >../actual.out 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "--no-recurse-submodules overrides config setting" '
-	add_upstream_commit &&
+	add_submodule_commits &&
 	(
 		cd downstream &&
 		git config fetch.recurseSubmodules true &&
@@ -246,36 +335,34 @@ test_expect_success "Recursion doesn't happen when no new commits are fetched in
 '
 
 test_expect_success "Recursion stops when no new submodule commits are fetched" '
-	head1=$(git rev-parse --short HEAD) &&
 	git add submodule &&
 	git commit -m "new submodule" &&
-	head2=$(git rev-parse --short HEAD) &&
-	echo "From $pwd/." > expect.err.sub &&
-	echo "   $head1..$head2  super      -> origin/super" >>expect.err.sub &&
-	head -3 expect.err >> expect.err.sub &&
+	new_head=$(git rev-parse --short HEAD) &&
+	write_expected_super $new_head &&
+	rm expect.err.deep &&
 	(
 		cd downstream &&
 		git fetch >../actual.out 2>../actual.err
 	) &&
-	test_cmp expect.err.sub actual.err &&
+	verify_fetch_result actual.err &&
 	test_must_be_empty actual.out
 '
 
 test_expect_success "Recursion doesn't happen when new superproject commits don't change any submodules" '
-	add_upstream_commit &&
-	head1=$(git rev-parse --short HEAD) &&
+	add_submodule_commits &&
 	echo a > file &&
 	git add file &&
 	git commit -m "new file" &&
-	head2=$(git rev-parse --short HEAD) &&
-	echo "From $pwd/." > expect.err.file &&
-	echo "   $head1..$head2  super      -> origin/super" >> expect.err.file &&
+	new_head=$(git rev-parse --short HEAD) &&
+	write_expected_super $new_head &&
+	rm expect.err.sub &&
+	rm expect.err.deep &&
 	(
 		cd downstream &&
 		git fetch >../actual.out 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err.file actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "Recursion picks up config in submodule" '
@@ -287,14 +374,11 @@ test_expect_success "Recursion picks up config in submodule" '
 			git config fetch.recurseSubmodules true
 		)
 	) &&
-	add_upstream_commit &&
-	head1=$(git rev-parse --short HEAD) &&
+	add_submodule_commits &&
 	git add submodule &&
 	git commit -m "new submodule" &&
-	head2=$(git rev-parse --short HEAD) &&
-	echo "From $pwd/." > expect.err.sub &&
-	echo "   $head1..$head2  super      -> origin/super" >> expect.err.sub &&
-	cat expect.err >> expect.err.sub &&
+	new_head=$(git rev-parse --short HEAD) &&
+	write_expected_super $new_head &&
 	(
 		cd downstream &&
 		git fetch >../actual.out 2>../actual.err &&
@@ -303,60 +387,23 @@ test_expect_success "Recursion picks up config in submodule" '
 			git config --unset fetch.recurseSubmodules
 		)
 	) &&
-	test_cmp expect.err.sub actual.err &&
+	verify_fetch_result actual.err &&
 	test_must_be_empty actual.out
 '
 
 test_expect_success "Recursion picks up all submodules when necessary" '
-	add_upstream_commit &&
-	(
-		cd submodule &&
-		(
-			cd subdir/deepsubmodule &&
-			git fetch &&
-			git checkout -q FETCH_HEAD
-		) &&
-		head1=$(git rev-parse --short HEAD^) &&
-		git add subdir/deepsubmodule &&
-		git commit -m "new deepsubmodule" &&
-		head2=$(git rev-parse --short HEAD) &&
-		echo "Fetching submodule submodule" > ../expect.err.sub &&
-		echo "From $pwd/submodule" >> ../expect.err.sub &&
-		echo "   $head1..$head2  sub        -> origin/sub" >> ../expect.err.sub
-	) &&
-	head1=$(git rev-parse --short HEAD) &&
-	git add submodule &&
-	git commit -m "new submodule" &&
-	head2=$(git rev-parse --short HEAD) &&
-	echo "From $pwd/." > expect.err.2 &&
-	echo "   $head1..$head2  super      -> origin/super" >> expect.err.2 &&
-	cat expect.err.sub >> expect.err.2 &&
-	tail -3 expect.err >> expect.err.2 &&
+	add_submodule_commits &&
+	add_superproject_commits &&
 	(
 		cd downstream &&
 		git fetch >../actual.out 2>../actual.err
 	) &&
-	test_cmp expect.err.2 actual.err &&
+	verify_fetch_result actual.err &&
 	test_must_be_empty actual.out
 '
 
 test_expect_success "'--recurse-submodules=on-demand' doesn't recurse when no new commits are fetched in the superproject (and ignores config)" '
-	add_upstream_commit &&
-	(
-		cd submodule &&
-		(
-			cd subdir/deepsubmodule &&
-			git fetch &&
-			git checkout -q FETCH_HEAD
-		) &&
-		head1=$(git rev-parse --short HEAD^) &&
-		git add subdir/deepsubmodule &&
-		git commit -m "new deepsubmodule" &&
-		head2=$(git rev-parse --short HEAD) &&
-		echo Fetching submodule submodule > ../expect.err.sub &&
-		echo "From $pwd/submodule" >> ../expect.err.sub &&
-		echo "   $head1..$head2  sub        -> origin/sub" >> ../expect.err.sub
-	) &&
+	add_submodule_commits &&
 	(
 		cd downstream &&
 		git config fetch.recurseSubmodules true &&
@@ -368,15 +415,8 @@ test_expect_success "'--recurse-submodules=on-demand' doesn't recurse when no ne
 '
 
 test_expect_success "'--recurse-submodules=on-demand' recurses as deep as necessary (and ignores config)" '
-	head1=$(git rev-parse --short HEAD) &&
-	git add submodule &&
-	git commit -m "new submodule" &&
-	head2=$(git rev-parse --short HEAD) &&
-	tail -3 expect.err > expect.err.deepsub &&
-	echo "From $pwd/." > expect.err &&
-	echo "   $head1..$head2  super      -> origin/super" >>expect.err &&
-	cat expect.err.sub >> expect.err &&
-	cat expect.err.deepsub >> expect.err &&
+	add_submodule_commits &&
+	add_superproject_commits &&
 	(
 		cd downstream &&
 		git config fetch.recurseSubmodules false &&
@@ -392,24 +432,165 @@ test_expect_success "'--recurse-submodules=on-demand' recurses as deep as necess
 		)
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err
+	verify_fetch_result actual.err
+'
+
+# These tests verify that we can fetch submodules that aren't in the
+# index.
+#
+# First, test the simple case where the index is empty and we only fetch
+# submodules that are not in the index.
+test_expect_success 'setup downstream branch without submodules' '
+	(
+		cd downstream &&
+		git checkout --recurse-submodules -b no-submodules &&
+		git rm .gitmodules &&
+		git rm submodule &&
+		git commit -m "no submodules" &&
+		git checkout --recurse-submodules super
+	)
+'
+
+test_expect_success "'--recurse-submodules=on-demand' should fetch submodule commits if the submodule is changed but the index has no submodules" '
+	add_submodule_commits &&
+	add_superproject_commits &&
+	# Fetch the new superproject commit
+	(
+		cd downstream &&
+		git switch --recurse-submodules no-submodules &&
+		git fetch --recurse-submodules=on-demand >../actual.out 2>../actual.err
+	) &&
+	super_head=$(git rev-parse --short HEAD) &&
+	sub_head=$(git -C submodule rev-parse --short HEAD) &&
+	deep_head=$(git -C submodule/subdir/deepsubmodule rev-parse --short HEAD) &&
+
+	# assert that these are fetched from commits, not the index
+	write_expected_sub $sub_head $super_head &&
+	write_expected_deep $deep_head $sub_head &&
+
+	test_must_be_empty actual.out &&
+	verify_fetch_result actual.err
+'
+
+test_expect_success "'--recurse-submodules' should fetch submodule commits if the submodule is changed but the index has no submodules" '
+	add_submodule_commits &&
+	add_superproject_commits &&
+	# Fetch the new superproject commit
+	(
+		cd downstream &&
+		git switch --recurse-submodules no-submodules &&
+		git fetch --recurse-submodules >../actual.out 2>../actual.err
+	) &&
+	super_head=$(git rev-parse --short HEAD) &&
+	sub_head=$(git -C submodule rev-parse --short HEAD) &&
+	deep_head=$(git -C submodule/subdir/deepsubmodule rev-parse --short HEAD) &&
+
+	# assert that these are fetched from commits, not the index
+	write_expected_sub $sub_head $super_head &&
+	write_expected_deep $deep_head $sub_head &&
+
+	test_must_be_empty actual.out &&
+	verify_fetch_result actual.err
+'
+
+test_expect_success "'--recurse-submodules' should ignore changed, inactive submodules" '
+	add_submodule_commits &&
+	add_superproject_commits &&
+
+	# Fetch the new superproject commit
+	(
+		cd downstream &&
+		git switch --recurse-submodules no-submodules &&
+		git -c submodule.submodule.active=false fetch --recurse-submodules >../actual.out 2>../actual.err
+	) &&
+	test_must_be_empty actual.out &&
+	super_head=$(git rev-parse --short HEAD) &&
+	write_expected_super $super_head &&
+	# Neither should be fetched because the submodule is inactive
+	rm expect.err.sub &&
+	rm expect.err.deep &&
+	verify_fetch_result actual.err
+'
+
+# Now that we know we can fetch submodules that are not in the index,
+# test that we can fetch index and non-index submodules in the same
+# operation.
+test_expect_success 'setup downstream branch with other submodule' '
+	mkdir submodule2 &&
+	(
+		cd submodule2 &&
+		git init &&
+		echo sub2content >sub2file &&
+		git add sub2file &&
+		git commit -a -m new &&
+		git branch -M sub2
+	) &&
+	git checkout -b super-sub2-only &&
+	git submodule add "$pwd/submodule2" submodule2 &&
+	git commit -m "add sub2" &&
+	git checkout super &&
+	(
+		cd downstream &&
+		git fetch --recurse-submodules origin &&
+		git checkout super-sub2-only &&
+		# Explicitly run "git submodule update" because sub2 is new
+		# and has not been cloned.
+		git submodule update --init &&
+		git checkout --recurse-submodules super
+	)
+'
+
+test_expect_success "'--recurse-submodules' should fetch submodule commits in changed submodules and the index" '
+	test_when_finished "rm expect.err.sub2" &&
+	# Create new commit in origin/super
+	add_submodule_commits &&
+	add_superproject_commits &&
+
+	# Create new commit in origin/super-sub2-only
+	git checkout super-sub2-only &&
+	(
+		cd submodule2 &&
+		test_commit --no-tag foo
+	) &&
+	git add submodule2 &&
+	git commit -m "new submodule2" &&
+
+	git checkout super &&
+	(
+		cd downstream &&
+		git fetch --recurse-submodules >../actual.out 2>../actual.err
+	) &&
+	test_must_be_empty actual.out &&
+	sub2_head=$(git -C submodule2 rev-parse --short HEAD) &&
+	super_head=$(git rev-parse --short super) &&
+	super_sub2_only_head=$(git rev-parse --short super-sub2-only) &&
+	write_expected_sub2 $sub2_head $super_sub2_only_head &&
+
+	# write_expected_super cannot handle >1 branch. Since this is a
+	# one-off, construct expect.err.super manually.
+	cat >"$pwd/expect.err.super" <<-EOF &&
+	From $pwd/.
+	   OLD_HEAD..$super_head  super           -> origin/super
+	   OLD_HEAD..$super_sub2_only_head  super-sub2-only -> origin/super-sub2-only
+	EOF
+	verify_fetch_result actual.err
 '
 
 test_expect_success "'--recurse-submodules=on-demand' stops when no new submodule commits are found in the superproject (and ignores config)" '
-	add_upstream_commit &&
-	head1=$(git rev-parse --short HEAD) &&
+	add_submodule_commits &&
 	echo a >> file &&
 	git add file &&
 	git commit -m "new file" &&
-	head2=$(git rev-parse --short HEAD) &&
-	echo "From $pwd/." > expect.err.file &&
-	echo "   $head1..$head2  super      -> origin/super" >> expect.err.file &&
+	new_head=$(git rev-parse --short HEAD) &&
+	write_expected_super $new_head &&
+	rm expect.err.sub &&
+	rm expect.err.deep &&
 	(
 		cd downstream &&
 		git fetch --recurse-submodules=on-demand >../actual.out 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err.file actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "'fetch.recurseSubmodules=on-demand' overrides global config" '
@@ -417,15 +598,13 @@ test_expect_success "'fetch.recurseSubmodules=on-demand' overrides global config
 		cd downstream &&
 		git fetch --recurse-submodules
 	) &&
-	add_upstream_commit &&
+	add_submodule_commits &&
 	git config --global fetch.recurseSubmodules false &&
-	head1=$(git rev-parse --short HEAD) &&
 	git add submodule &&
 	git commit -m "new submodule" &&
-	head2=$(git rev-parse --short HEAD) &&
-	echo "From $pwd/." > expect.err.2 &&
-	echo "   $head1..$head2  super      -> origin/super" >>expect.err.2 &&
-	head -3 expect.err >> expect.err.2 &&
+	new_head=$(git rev-parse --short HEAD) &&
+	write_expected_super $new_head &&
+	rm expect.err.deep &&
 	(
 		cd downstream &&
 		git config fetch.recurseSubmodules on-demand &&
@@ -437,7 +616,7 @@ test_expect_success "'fetch.recurseSubmodules=on-demand' overrides global config
 		git config --unset fetch.recurseSubmodules
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err.2 actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "'submodule.<sub>.fetchRecurseSubmodules=on-demand' overrides fetch.recurseSubmodules" '
@@ -445,15 +624,13 @@ test_expect_success "'submodule.<sub>.fetchRecurseSubmodules=on-demand' override
 		cd downstream &&
 		git fetch --recurse-submodules
 	) &&
-	add_upstream_commit &&
+	add_submodule_commits &&
 	git config fetch.recurseSubmodules false &&
-	head1=$(git rev-parse --short HEAD) &&
 	git add submodule &&
 	git commit -m "new submodule" &&
-	head2=$(git rev-parse --short HEAD) &&
-	echo "From $pwd/." > expect.err.2 &&
-	echo "   $head1..$head2  super      -> origin/super" >>expect.err.2 &&
-	head -3 expect.err >> expect.err.2 &&
+	new_head=$(git rev-parse --short HEAD) &&
+	write_expected_super $new_head &&
+	rm expect.err.deep &&
 	(
 		cd downstream &&
 		git config submodule.submodule.fetchRecurseSubmodules on-demand &&
@@ -465,7 +642,7 @@ test_expect_success "'submodule.<sub>.fetchRecurseSubmodules=on-demand' override
 		git config --unset submodule.submodule.fetchRecurseSubmodules
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err.2 actual.err
+	verify_fetch_result actual.err
 '
 
 test_expect_success "don't fetch submodule when newly recorded commits are already present" '
@@ -473,18 +650,19 @@ test_expect_success "don't fetch submodule when newly recorded commits are alrea
 		cd submodule &&
 		git checkout -q HEAD^^
 	) &&
-	head1=$(git rev-parse --short HEAD) &&
 	git add submodule &&
 	git commit -m "submodule rewound" &&
-	head2=$(git rev-parse --short HEAD) &&
-	echo "From $pwd/." > expect.err &&
-	echo "   $head1..$head2  super      -> origin/super" >> expect.err &&
+	new_head=$(git rev-parse --short HEAD) &&
+	write_expected_super $new_head &&
+	rm expect.err.sub &&
+	# This file does not exist, but rm -f for readability
+	rm -f expect.err.deep &&
 	(
 		cd downstream &&
 		git fetch >../actual.out 2>../actual.err
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err actual.err &&
+	verify_fetch_result actual.err &&
 	(
 		cd submodule &&
 		git checkout -q sub
@@ -496,15 +674,13 @@ test_expect_success "'fetch.recurseSubmodules=on-demand' works also without .git
 		cd downstream &&
 		git fetch --recurse-submodules
 	) &&
-	add_upstream_commit &&
-	head1=$(git rev-parse --short HEAD) &&
+	add_submodule_commits &&
 	git add submodule &&
 	git rm .gitmodules &&
 	git commit -m "new submodule without .gitmodules" &&
-	head2=$(git rev-parse --short HEAD) &&
-	echo "From $pwd/." >expect.err.2 &&
-	echo "   $head1..$head2  super      -> origin/super" >>expect.err.2 &&
-	head -3 expect.err >>expect.err.2 &&
+	new_head=$(git rev-parse --short HEAD) &&
+	write_expected_super $new_head &&
+	rm expect.err.deep &&
 	(
 		cd downstream &&
 		rm .gitmodules &&
@@ -520,7 +696,7 @@ test_expect_success "'fetch.recurseSubmodules=on-demand' works also without .git
 		git reset --hard
 	) &&
 	test_must_be_empty actual.out &&
-	test_cmp expect.err.2 actual.err &&
+	verify_fetch_result actual.err &&
 	git checkout HEAD^ -- .gitmodules &&
 	git add .gitmodules &&
 	git commit -m "new submodule restored .gitmodules"
@@ -842,4 +1018,111 @@ test_expect_success 'recursive fetch after deinit a submodule' '
 	test_cmp expect actual
 '
 
+test_expect_success 'setup repo with upstreams that share a submodule name' '
+	mkdir same-name-1 &&
+	(
+		cd same-name-1 &&
+		git init -b main &&
+		test_commit --no-tag a
+	) &&
+	git clone same-name-1 same-name-2 &&
+	# same-name-1 and same-name-2 both add a submodule with the
+	# name "submodule"
+	(
+		cd same-name-1 &&
+		mkdir submodule &&
+		git -C submodule init -b main &&
+		test_commit -C submodule --no-tag a1 &&
+		git submodule add "$pwd/same-name-1/submodule" &&
+		git add submodule &&
+		git commit -m "super-a1"
+	) &&
+	(
+		cd same-name-2 &&
+		mkdir submodule &&
+		git -C submodule init -b main &&
+		test_commit -C submodule --no-tag a2 &&
+		git submodule add "$pwd/same-name-2/submodule" &&
+		git add submodule &&
+		git commit -m "super-a2"
+	) &&
+	git clone same-name-1 -o same-name-1 same-name-downstream &&
+	(
+		cd same-name-downstream &&
+		git remote add same-name-2 ../same-name-2 &&
+		git fetch --all &&
+		# init downstream with same-name-1
+		git submodule update --init
+	)
+'
+
+test_expect_success 'fetch --recurse-submodules updates name-conflicted, populated submodule' '
+	test_when_finished "git -C same-name-downstream checkout main" &&
+	(
+		cd same-name-1 &&
+		test_commit -C submodule --no-tag b1 &&
+		git add submodule &&
+		git commit -m "super-b1"
+	) &&
+	(
+		cd same-name-2 &&
+		test_commit -C submodule --no-tag b2 &&
+		git add submodule &&
+		git commit -m "super-b2"
+	) &&
+	(
+		cd same-name-downstream &&
+		# even though the .gitmodules is correct, we cannot
+		# fetch from same-name-2
+		git checkout same-name-2/main &&
+		git fetch --recurse-submodules same-name-1 &&
+		test_must_fail git fetch --recurse-submodules same-name-2
+	) &&
+	super_head1=$(git -C same-name-1 rev-parse HEAD) &&
+	git -C same-name-downstream cat-file -e $super_head1 &&
+
+	super_head2=$(git -C same-name-2 rev-parse HEAD) &&
+	git -C same-name-downstream cat-file -e $super_head2 &&
+
+	sub_head1=$(git -C same-name-1/submodule rev-parse HEAD) &&
+	git -C same-name-downstream/submodule cat-file -e $sub_head1 &&
+
+	sub_head2=$(git -C same-name-2/submodule rev-parse HEAD) &&
+	test_must_fail git -C same-name-downstream/submodule cat-file -e $sub_head2
+'
+
+test_expect_success 'fetch --recurse-submodules updates name-conflicted, unpopulated submodule' '
+	(
+		cd same-name-1 &&
+		test_commit -C submodule --no-tag c1 &&
+		git add submodule &&
+		git commit -m "super-c1"
+	) &&
+	(
+		cd same-name-2 &&
+		test_commit -C submodule --no-tag c2 &&
+		git add submodule &&
+		git commit -m "super-c2"
+	) &&
+	(
+		cd same-name-downstream &&
+		git checkout main &&
+		git rm .gitmodules &&
+		git rm submodule &&
+		git commit -m "no submodules" &&
+		git fetch --recurse-submodules same-name-1
+	) &&
+	head1=$(git -C same-name-1/submodule rev-parse HEAD) &&
+	head2=$(git -C same-name-2/submodule rev-parse HEAD) &&
+	(
+		cd same-name-downstream/.git/modules/submodule &&
+		# The submodule has core.worktree pointing to the "git
+		# rm"-ed directory, overwrite the invalid value. See
+		# comment in get_fetch_task_from_changed() for more
+		# information.
+		git --work-tree=. cat-file -e $head1 &&
+		test_must_fail git --work-tree=. cat-file -e $head2
+	)
+'
+
 test_done