stash: use merge-ort rather than merge-recursive

Because `merge_recursive` forces the index to always be expanded, switching to
`merge_ort_recursive` is needed to allow the index to remain sparse when
applying a stash.

Signed-off-by: Victoria Dye <vdye@github.com>

builtin/stash.c

@@ -7,6 +7,7 @@
 #include "cache-tree.h"
 #include "unpack-trees.h"
 #include "merge-recursive.h"
+#include "merge-ort-wrappers.h"
 #include "strvec.h"
 #include "run-command.h"
 #include "dir.h"
@@ -554,7 +555,7 @@ static int do_apply_stash(const char *prefix, struct stash_info *info,
 	bases[0] = &info->b_tree;
 
 	ret = merge_recursive_generic(&o, &c_tree, &info->w_tree, 1, bases,
-				      merge_recursive, &result);
+				      merge_ort_recursive, &result);
 	if (ret) {
 		rerere(0);
 

t/t1092-sparse-checkout-compatibility.sh

@@ -1212,12 +1212,15 @@ test_expect_success 'sparse-index is not expanded' '
 	ensure_not_expanded stash &&
 	ensure_not_expanded stash list &&
 	ensure_not_expanded stash show stash@{0} &&
+	ensure_not_expanded stash apply stash@{0} &&
 	ensure_not_expanded stash drop stash@{0} &&
 
 	ensure_not_expanded stash create &&
 	oid=$(git -C sparse-index stash create) &&
 	ensure_not_expanded stash store -m "test" $oid &&
 	ensure_not_expanded reset --hard &&
+	ensure_not_expanded stash pop &&
+
 	ensure_not_expanded checkout-index -f a &&
 	ensure_not_expanded checkout-index -f --all &&
 	for ref in update-deep update-folder1 update-folder2 update-deep