[RFC PATCH 3/4] fsck: support referenced lazy objects

[Jonathan Tan <jonathantanmy@google.com>]

Teach fsck to not treat missing objects indirectly pointed to by refs as
an error when extensions.lazyobject is set.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
---
 builtin/fsck.c         | 11 +++++++++++
 t/t0410-lazy-object.sh | 27 +++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/builtin/fsck.c b/builtin/fsck.c
index e29ff760b..238532cc2 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -149,6 +149,15 @@ static int mark_object(struct object *obj, int type, void *data, struct fsck_opt
 		return 0;
 	obj->flags |= REACHABLE;
 	if (!(obj->flags & HAS_OBJ)) {
+		if (repository_format_lazy_object)
+			/*
+			 * Return immediately; this is not an error, and further
+			 * recursion does not need to be performed on this
+			 * object since it is missing (so it does not need to be
+			 * added to "pending").
+			 */
+			return 0;
+
 		if (parent && !has_object_file(&obj->oid)) {
 			printf("broken link from %7s %s\n",
 				 printable_type(parent), describe_object(parent));
@@ -212,6 +221,8 @@ static void check_reachable_object(struct object *obj)
 	 * do a full fsck
 	 */
 	if (!(obj->flags & HAS_OBJ)) {
+		if (repository_format_lazy_object)
+			return;
 		if (has_sha1_pack(obj->oid.hash))
 			return; /* it is in pack - forget about it */
 		printf("missing %s %s\n", printable_type(obj),
diff --git a/t/t0410-lazy-object.sh b/t/t0410-lazy-object.sh
index 00e1b4a88..45f665a15 100755
--- a/t/t0410-lazy-object.sh
+++ b/t/t0410-lazy-object.sh
@@ -49,4 +49,31 @@ test_expect_success '...but succeeds if lazyobject is set' '
 	git -C repo fsck
 '
 
+test_expect_success 'fsck fails on lazy object indirectly pointed to by ref' '
+	rm -rf repo &&
+	test_create_repo repo &&
+	test_commit -C repo 1 &&
+	test_commit -C repo 2 &&
+	test_commit -C repo 3 &&
+	git -C repo tag -a annotated_tag -m "annotated tag" &&
+
+	C=$(git -C repo rev-parse 1) &&
+	T=$(git -C repo rev-parse 2^{tree}) &&
+	B=$(git hash-object repo/3.t) &&
+	AT=$(git -C repo rev-parse annotated_tag) &&
+
+	# missing commit, tree, blob, and tag
+	delete_object repo "$C" &&
+	delete_object repo "$T" &&
+	delete_object repo "$B" &&
+	delete_object repo "$AT" &&
+	test_must_fail git -C repo fsck
+'
+
+test_expect_success '...but succeeds if lazyobject is set' '
+	git -C repo config core.repositoryformatversion 1 &&
+	git -C repo config extensions.lazyobject "arbitrary string" &&
+	git -C repo fsck
+'
+
 test_done
-- 
2.14.0.rc0.400.g1c36432dff-goog