[PATCH] submodule: check for NULL return of get_submodule_ref_store()

[Stefan Beller]

From: René Scharfe <l....@web.de>

If we can't find a ref store for a submodule then assume it the latter
is not initialized (or was removed).  Print a status line accordingly
instead of causing a segmentation fault by passing NULL as the first
parameter of refs_head_ref().

Reported-by: Jeremy Feusi <jer...@feusi.co>
Signed-off-by: Rene Scharfe <l....@web.de>
Signed-off-by: Stefan Beller <sbel...@google.com>
---

I added a test for you.

Thanks,
Stefan

 builtin/submodule--helper.c |  8 ++++++--
 t/t7400-submodule-basic.sh  | 12 ++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index ee020d4749..ae3014ac5a 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -654,9 +654,13 @@ static void status_submodule(const char *path, const 
struct object_id *ce_oid,
                             displaypath);
        } else if (!(flags & OPT_CACHED)) {
                struct object_id oid;
+               struct ref_store *refs = get_submodule_ref_store(path);
 
-               if (refs_head_ref(get_submodule_ref_store(path),
-                                 handle_submodule_head_ref, &oid))
+               if (!refs) {
+                       print_status(flags, '-', path, ce_oid, displaypath);
+                       goto cleanup;
+               }
+               if (refs_head_ref(refs, handle_submodule_head_ref, &oid))
                        die(_("could not resolve HEAD ref inside the "
                              "submodule '%s'"), path);
 
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index a39e69a3eb..d8aee51603 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -821,6 +821,18 @@ test_expect_success 'moving the superproject does not 
break submodules' '
        )
 '
 
+test_expect_success 'moving the submodule does not break the superproject' '
+       (
+               cd addtest2 &&
+
+               mv repo repo.bak &&
+               git submodule status >actual &&
+               grep -e "^-" -e repo actual &&
+
+               mv repo.bak repo
+       )
+'
+
 test_expect_success 'submodule add --name allows to replace a submodule with 
another at the same path' '
        (
                cd addtest2 &&
-- 
2.17.0.rc1.321.gba9d0f2565-goog