merge-ort: unconditionally release attributes index

We conditionally release the index used for reading gitattributes in
merge-ort based on whether or the index has been populated. This check
uses `cache_nr` as a condition. This isn't sufficient though, as the
variable may be zero even when some other parts of the index have been
populated. This leads to memory leaks when sparse checkouts are in use,
as we may not end up releasing the sparse checkout patterns.

Fix this issue by unconditionally releasing the index.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

merge-ort.c

@@ -689,8 +689,7 @@ static void clear_or_reinit_internal_opts(struct merge_options_internal *opti,
 	 */
 	strmap_clear_func(&opti->conflicted, 0);
 
-	if (opti->attr_index.cache_nr) /* true iff opt->renormalize */
-		discard_index(&opti->attr_index);
+	discard_index(&opti->attr_index);
 
 	/* Free memory used by various renames maps */
 	for (i = MERGE_SIDE1; i <= MERGE_SIDE2; ++i) {

t/t3507-cherry-pick-conflict.sh

@@ -13,6 +13,7 @@ GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 TEST_CREATE_REPO_NO_TEMPLATE=1
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 pristine_detach () {

t/t6421-merge-partial-clone.sh

@@ -26,6 +26,7 @@ test_description="limiting blob downloads when merging with partial clones"
 #                     underscore notation is to differentiate different
 #                     files that might be renamed into each other's paths.)
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-merge.sh
 

t/t6428-merge-conflicts-sparse.sh

@@ -22,6 +22,7 @@ test_description="merge cases"
 #                     underscore notation is to differentiate different
 #                     files that might be renamed into each other's paths.)
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-merge.sh
 

t/t7817-grep-sparse-checkout.sh

@@ -33,6 +33,7 @@ should leave the following structure in the working tree:
 But note that sub2 should have the SKIP_WORKTREE bit set.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '