Merge branch 'sb/fix-fetching-moved-submodules'

The code to try seeing if a fetch is necessary in a submodule
during a fetch with --recurse-submodules got confused when the path
to the submodule was changed in the range of commits in the
superproject, sometimes showing "(null)".  This has been corrected.

* sb/fix-fetching-moved-submodules:
  t5526: test recursive submodules when fetching moved submodules
  submodule: fix NULL correctness in renamed broken submodules

Author: gitster

submodule.c

@@ -740,12 +740,14 @@ static void collect_changed_submodules_cb(struct diff_queue_struct *q,
 		else {
 			name = default_name_or_path(p->two->path);
 			/* make sure name does not collide with existing one */
-			submodule = submodule_from_name(the_repository, commit_oid, name);
+			if (name)
+				submodule = submodule_from_name(the_repository,
+								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), name);
+					oid_to_hex(commit_oid), p->two->path);
 				name = NULL;
 			}
 		}

t/t5526-fetch-submodules.sh

@@ -574,11 +574,7 @@ test_expect_success "fetch new commits when submodule got renamed" '
 	git clone . downstream_rename &&
 	(
 		cd downstream_rename &&
-		git submodule update --init &&
-# NEEDSWORK: we omitted --recursive for the submodule update here since
-# that does not work. See test 7001 for mv "moving nested submodules"
-# for details. Once that is fixed we should add the --recursive option
-# here.
+		git submodule update --init --recursive &&
 		git checkout -b rename &&
 		git mv submodule submodule_renamed &&
 		(