Merge branch 'sb/submodule-update-reset-fix' into maint

When resetting the working tree files recursively, the working tree
of submodules are now also reset to match.

* sb/submodule-update-reset-fix:
  submodule: submodule_move_head omits old argument in forced case
  unpack-trees: oneway_merge to update submodules
  t/lib-submodule-update.sh: fix test ignoring ignored files in submodules
  t/lib-submodule-update.sh: clarify test

Author: gitster

submodule.c

@@ -1657,7 +1657,9 @@ int submodule_move_head(const char *path,
 	else
 		argv_array_push(&cp.args, "-m");
 
-	argv_array_push(&cp.args, old ? old : EMPTY_TREE_SHA1_HEX);
+	if (!(flags & SUBMODULE_MOVE_HEAD_FORCE))
+		argv_array_push(&cp.args, old ? old : EMPTY_TREE_SHA1_HEX);
+
 	argv_array_push(&cp.args, new ? new : EMPTY_TREE_SHA1_HEX);
 
 	if (run_command(&cp)) {

t/lib-submodule-update.sh

@@ -664,8 +664,8 @@ test_submodule_recursing_with_args_common() {
 			cd submodule_update &&
 			git -C sub1 checkout -b keep_branch &&
 			git -C sub1 rev-parse HEAD >expect &&
-			git branch -t check-keep origin/modify_sub1 &&
-			$command check-keep &&
+			git branch -t modify_sub1 origin/modify_sub1 &&
+			$command modify_sub1 &&
 			test_superproject_content origin/modify_sub1 &&
 			test_submodule_content sub1 origin/modify_sub1 &&
 			git -C sub1 rev-parse keep_branch >actual &&
@@ -885,6 +885,7 @@ test_submodule_switch_recursing_with_args () {
 		(
 			cd submodule_update &&
 			git branch -t replace_sub1_with_file origin/replace_sub1_with_file &&
+			echo ignored >.git/modules/sub1/info/exclude &&
 			: >sub1/ignored &&
 			$command replace_sub1_with_file &&
 			test_superproject_content origin/replace_sub1_with_file &&
@@ -1014,4 +1015,18 @@ test_submodule_forced_switch_recursing_with_args () {
 			test_submodule_content sub1 origin/modify_sub1
 		)
 	'
+
+	test_expect_success "$command: changed submodule worktree is reset" '
+		prolog &&
+		reset_work_tree_to_interested add_sub1 &&
+		(
+			cd submodule_update &&
+			rm sub1/file1 &&
+			: >sub1/new_file &&
+			git -C sub1 add new_file &&
+			$command HEAD &&
+			test_path_is_file sub1/file1 &&
+			test_path_is_missing sub1/new_file
+		)
+	'
 }

unpack-trees.c

@@ -2139,6 +2139,9 @@ int oneway_merge(const struct cache_entry * const *src,
 			    ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
 				update |= CE_UPDATE;
 		}
+		if (o->update && S_ISGITLINK(old->ce_mode) &&
+		    should_update_submodules() && !verify_uptodate(old, o))
+			update |= CE_UPDATE;
 		add_entry(o, old, update, 0);
 		return 0;
 	}