checkout-index: integrate with sparse index

Add repository settings to allow usage of the sparse index. In order to prevent
unexpected errors when attempting to check out a sparse directory entry,
`checkout_file` directly checks whether a found entry is a sparse directory
and, if so, exits with an error. The test corresponding to this case now
verifies the error message, intentionally differing from the non-sparse index
scenarios.

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

Author: vdye

builtin/checkout-index.c

@@ -66,6 +66,7 @@ static int checkout_file(const char *name, const char *prefix)
 	int namelen = strlen(name);
 	int pos = cache_name_pos(name, namelen);
 	int has_same_name = 0;
+	int is_file = 0;
 	int did_checkout = 0;
 	int errs = 0;
 
@@ -79,6 +80,9 @@ static int checkout_file(const char *name, const char *prefix)
 			break;
 		has_same_name = 1;
 		pos++;
+		if (S_ISSPARSEDIR(ce->ce_mode))
+			break;
+		is_file = 1;
 		if (ce_stage(ce) != checkout_stage
 		    && (CHECKOUT_ALL != checkout_stage || !ce_stage(ce)))
 			continue;
@@ -107,6 +111,8 @@ static int checkout_file(const char *name, const char *prefix)
 		fprintf(stderr, "git checkout-index: %s ", name);
 		if (!has_same_name)
 			fprintf(stderr, "is not in the cache");
+		else if (!is_file)
+			fprintf(stderr, "is a sparse directory");
 		else if (checkout_stage)
 			fprintf(stderr, "does not exist at stage %d",
 				checkout_stage);
@@ -218,6 +224,9 @@ int cmd_checkout_index(int argc, const char **argv, const char *prefix)
 	git_config(git_default_config, NULL);
 	prefix_length = prefix ? strlen(prefix) : 0;
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	if (read_cache() < 0) {
 		die("invalid cache");
 	}

t/t1092-sparse-checkout-compatibility.sh

@@ -924,7 +924,14 @@ test_expect_success 'checkout-index with folders' '
 	test_all_match test_must_fail git checkout-index -f -- deep/ &&
 
 	# Outside checkout definition
-	test_all_match test_must_fail git checkout-index -f -- folder1/
+	# Note: although all tests fail (as expected), the messaging differs. For
+	# non-sparse index checkouts, the error is that the "file" does not appear
+	# in the index; for sparse checkouts, the error is explicitly that the
+	# entry is a sparse directory.
+	run_on_all test_must_fail git checkout-index -f -- folder1/ &&
+	test_cmp full-checkout-err sparse-checkout-err &&
+	! test_cmp full-checkout-err sparse-index-err &&
+	grep "is a sparse directory" sparse-index-err
 '
 
 test_expect_success 'checkout-index --all' '
@@ -1037,6 +1044,7 @@ test_expect_success 'sparse-index is not expanded' '
 	echo >>sparse-index/untracked.txt &&
 	ensure_not_expanded add . &&
 
+	ensure_not_expanded checkout-index -f a &&
 	for ref in update-deep update-folder1 update-folder2 update-deep
 	do
 		echo >>sparse-index/README.md &&