Merge branch 'sb/submodule-recursive-fetch-gets-the-tip'

"git fetch --recurse-submodules" may not fetch the necessary commit
that is bound to the superproject, which is getting corrected.

* sb/submodule-recursive-fetch-gets-the-tip:
  fetch: ensure submodule objects fetched
  submodule.c: fetch in submodules git directory instead of in worktree
  submodule: migrate get_next_submodule to use repository structs
  repository: repo_submodule_init to take a submodule struct
  submodule: store OIDs in changed_submodule_names
  submodule.c: tighten scope of changed_submodule_names struct
  submodule.c: sort changed_submodule_names before searching it
  submodule.c: fix indentation
  sha1-array: provide oid_array_filter

diff --cc builtin/fetch.c
Simple merge

diff --cc builtin/grep.c
index 4748195ae173786924f75dab9e865ce05b434930,d6bd887b2df28c873cc4b10bab839e5fbe287b83..dc9183876499e30e00f81b10c74c54270160448d
--- 1/builtin/grep.c
--- 2/builtin/grep.c
+++ b/builtin/grep.c
@@@ -437,7 -440,7 +440,7 @@@ static int grep_submodule(struct grep_o
         * store is no longer global and instead is a member of the repository
         * object.
         */
-       add_to_alternates_memory(submodule.objects->odb->path);
 -      add_to_alternates_memory(subrepo.objects->objectdir);
++      add_to_alternates_memory(subrepo.objects->odb->path);
        grep_read_unlock();
  
        if (oid) {

diff --cc builtin/ls-files.c
Simple merge

diff --cc builtin/submodule--helper.c
Simple merge

diff --cc repository.c
Simple merge

diff --cc submodule.c
Simple merge

diff --cc t/t5526-fetch-submodules.sh
Simple merge