The first attempt to fix this regression, in 1b7ac4e6d4 (submodules:
fix of regression on fetching of non-init subsub-repo, 2020-11-12), by
simply reverting a62387b, resulted in an infinite loop of submodule
fetches in the simpler case of a recursive fetch of a superproject with
uninitialized submodules, and so this commit was reverted in 7091499bc0
(Revert "submodules: fix of regression on fetching of non-init
subsub-repo", 2020-12-02).
To prevent future breakages, also add a regression test for this
scenario.

Signed-off-by: Peter Kaestle <redacted>
CC: Junio C Hamano <redacted>
CC: Philippe Blain <redacted>
CC: Ralf Thielow <redacted>
CC: Philippe Blain <redacted>
---
 submodule.c                 |   7 ++-
 t/t5526-fetch-submodules.sh | 124 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 130 insertions(+), 1 deletion(-)

diff --git a/submodule.c b/submodule.c
index b3bb59f..b561445 100644
--- a/submodule.c
+++ b/submodule.c

@@ -1477,6 +1477,7 @@ static int get_next_submodule(struct child_process *cp,
                        strbuf_release(&submodule_prefix);
                        return 1;
                } else {
+                       struct strbuf empty_submodule_path = STRBUF_INIT;

                        fetch_task_release(task);
                        free(task);

@@ -1485,13 +1486,17 @@ static int get_next_submodule(struct child_process *cp,
                         * An empty directory is normal,
                         * the submodule is not initialized
                         */
+                       strbuf_addf(&empty_submodule_path, "%s/%s/",
+                                                       spf->r->worktree,
+                                                       ce->name);
                        if (S_ISGITLINK(ce->ce_mode) &&
-                           !is_empty_dir(ce->name)) {
+                           !is_empty_dir(empty_submodule_path.buf)) {
                                spf->result = 1;
                                strbuf_addf(err,
                                            _("Could not access submodule '%s'\n"),
                                            ce->name);
                        }
+                       strbuf_release(&empty_submodule_path);
                }
        }

diff --git a/t/t5526-fetch-submodules.sh b/t/t5526-fetch-submodules.sh
index dd8e423..495348a 100755
--- a/t/t5526-fetch-submodules.sh
+++ b/t/t5526-fetch-submodules.sh

@@ -719,4 +719,128 @@ test_expect_success 'fetch new submodule commit intermittently referenced by sup
        )
 '

+add_commit_push () {
+       dir="$1" &&
+       msg="$2" &&
+       shift 2 &&
+       git -C "$dir" add "$@" &&
+       git -C "$dir" commit -a -m "$msg" &&
+       git -C "$dir" push
+}
+
+compare_refs_in_dir () {
+       fail= &&
+       if test "x$1" = 'x!'
+       then
+               fail='!' &&
+               shift
+       fi &&
+       git -C "$1" rev-parse --verify "$2" >expect &&
+       git -C "$3" rev-parse --verify "$4" >actual &&
+       eval $fail test_cmp expect actual
+}
+
+
+test_expect_success 'setup nested submodule fetch test' '
+       # does not depend on any previous test setups
+
+       for repo in outer middle inner
+       do
+               git init --bare $repo &&
+               git clone $repo ${repo}_content &&
+               echo "$repo" >"${repo}_content/file" &&
+               add_commit_push ${repo}_content "initial" file ||
+               return 1
+       done &&
+
+       git clone outer A &&
+       git -C A submodule add "$pwd/middle" &&
+       git -C A/middle/ submodule add "$pwd/inner" &&
+       add_commit_push A/middle/ "adding inner sub" .gitmodules inner &&
+       add_commit_push A/ "adding middle sub" .gitmodules middle &&
+
+       git clone outer B &&
+       git -C B/ submodule update --init middle &&
+
+       compare_refs_in_dir A HEAD B HEAD &&
+       compare_refs_in_dir A/middle HEAD B/middle HEAD &&
+       test_path_is_file B/file &&
+       test_path_is_file B/middle/file &&
+       test_path_is_missing B/middle/inner/file &&
+
+       echo "change on inner repo of A" >"A/middle/inner/file" &&
+       add_commit_push A/middle/inner "change on inner" file &&
+       add_commit_push A/middle "change on inner" inner &&
+       add_commit_push A "change on inner" middle
+'
+
+test_expect_success 'fetching a superproject containing an uninitialized sub/sub project' '
+       # depends on previous test for setup
+
+       git -C B/ fetch &&
+       compare_refs_in_dir A origin/HEAD B origin/HEAD
+'
+
+fetch_with_recusion_abort () {