clean: integrate with sparse index

Add repository setting to not require full index and test to verify index is
not expanded in `git clean`. Existing test for `git clean` expanded to verify
behavior when cleaning untracked files in sparse directories is consistent.

Signed-off-by: Victoria Dye <[email protected]>

Author: vdye

builtin/clean.c

@@ -1010,6 +1010,9 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
 		dir.flags |= DIR_KEEP_UNTRACKED_CONTENTS;
 	}
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	if (read_cache() < 0)
 		die(_("index file corrupt"));
 	enable_fscache(active_nr);

t/t1092-sparse-checkout-compatibility.sh

@@ -1068,23 +1068,42 @@ test_expect_success 'clean' '
 	test_all_match git commit -m "ignore bogus files" &&
 
 	run_on_sparse mkdir folder1 &&
+	run_on_all mkdir -p deep/untracked-deep &&
 	run_on_all touch folder1/bogus &&
+	run_on_all touch folder1/untracked &&
+	run_on_all touch deep/untracked-deep/bogus &&
+	run_on_all touch deep/untracked-deep/untracked &&
 
 	test_all_match git status --porcelain=v2 &&
 	test_all_match git clean -f &&
 	test_all_match git status --porcelain=v2 &&
 	test_sparse_match ls &&
 	test_sparse_match ls folder1 &&
+	run_on_all test_path_exists folder1/bogus &&
+	run_on_all test_path_is_missing folder1/untracked &&
+	run_on_all test_path_exists deep/untracked-deep/bogus &&
+	run_on_all test_path_exists deep/untracked-deep/untracked &&
+
+	test_all_match git clean -fd &&
+	test_all_match git status --porcelain=v2 &&
+	test_sparse_match ls &&
+	test_sparse_match ls folder1 &&
+	run_on_all test_path_exists folder1/bogus &&
+	run_on_all test_path_exists deep/untracked-deep/bogus &&
+	run_on_all test_path_is_missing deep/untracked-deep/untracked &&
 
 	test_all_match git clean -xf &&
 	test_all_match git status --porcelain=v2 &&
 	test_sparse_match ls &&
 	test_sparse_match ls folder1 &&
+	run_on_all test_path_is_missing folder1/bogus &&
+	run_on_all test_path_exists deep/untracked-deep/bogus &&
 
 	test_all_match git clean -xdf &&
 	test_all_match git status --porcelain=v2 &&
 	test_sparse_match ls &&
 	test_sparse_match ls folder1 &&
+	run_on_all test_path_is_missing deep/untracked-deep/bogus &&
 
 	test_sparse_match test_path_is_dir folder1
 '
@@ -1202,6 +1221,8 @@ test_expect_success 'sparse-index is not expanded' '
 	git -C sparse-index add README.md &&
 	ensure_not_expanded diff --staged &&
 
+	ensure_not_expanded clean -fd &&
+
 	ensure_not_expanded checkout -f update-deep &&
 	(
 		sane_unset GIT_TEST_MERGE_ALGORITHM &&