diff --git a/src/tree-cache.c b/src/tree-cache.c
index 48dc46a40..bf52b5530 100644
--- a/src/tree-cache.c
+++ b/src/tree-cache.c
@@ -280,10 +280,8 @@ static void write_tree(git_buf *out, git_tree_cache *tree)
 
 	git_buf_printf(out, "%s%c%zd %"PRIuZ"\n", tree->name, 0, tree->entry_count, tree->children_count);
 
-	if (tree->entry_count == -1)
-		return;
-
-	git_buf_put(out, (const char *) &tree->oid, GIT_OID_RAWSZ);
+	if (tree->entry_count != -1)
+		git_buf_put(out, (const char *) &tree->oid, GIT_OID_RAWSZ);
 
 	for (i = 0; i < tree->children_count; i++)
 		write_tree(out, tree->children[i]);
diff --git a/tests/index/cache.c b/tests/index/cache.c
index ba2d51fa2..17a61a9f5 100644
--- a/tests/index/cache.c
+++ b/tests/index/cache.c
@@ -119,6 +119,59 @@ void test_index_cache__read_tree_no_children(void)
 	git_index_free(index);
 }
 
+void test_index_cache__two_levels(void)
+{
+	git_tree *tree;
+	git_oid tree_id;
+	git_index *index;
+	git_index_entry entry;
+	const git_tree_cache *tree_cache;
+
+	cl_git_pass(git_repository_index(&index, g_repo));
+	cl_git_pass(git_index_clear(index));
+
+	memset(&entry, 0x0, sizeof(entry));
+	entry.mode = GIT_FILEMODE_BLOB;
+	cl_git_pass(git_oid_fromstr(&entry.id, "a8233120f6ad708f843d861ce2b7228ec4e3dec6"));
+	entry.path = "top-level.txt";
+	cl_git_pass(git_index_add(index, &entry));
+
+	entry.path = "subdir/file.txt";
+	cl_git_pass(git_index_add(index, &entry));
+
+	/* the read-tree fills the tree cache */
+	cl_git_pass(git_index_write_tree(&tree_id, index));
+	cl_git_pass(git_tree_lookup(&tree, g_repo, &tree_id));
+	cl_git_pass(git_index_read_tree(index, tree));
+	git_tree_free(tree);
+	cl_git_pass(git_index_write(index));
+
+	/* we now must have cache entries for "" and "subdir" */
+	cl_assert(index->tree);
+	cl_assert(git_tree_cache_get(index->tree, "subdir"));
+
+	cl_git_pass(git_index_read(index, true));
+	/* we must still have cache entries for "" and "subdir", since we wrote it out */
+	cl_assert(index->tree);
+	cl_assert(git_tree_cache_get(index->tree, "subdir"));
+
+	entry.path = "top-level.txt";
+	cl_git_pass(git_oid_fromstr(&entry.id, "3697d64be941a53d4ae8f6a271e4e3fa56b022cc"));
+	cl_git_pass(git_index_add(index, &entry));
+
+	/* writ out the index after we invalidate the root */
+	cl_git_pass(git_index_write(index));
+	cl_git_pass(git_index_read(index, true));
+
+	/* the cache for the subtree must still be valid, even if the root isn't */
+	cl_assert(index->tree);
+	cl_assert_equal_i(-1, index->tree->entry_count);
+	cl_assert_equal_i(1, index->tree->children_count);
+	tree_cache = git_tree_cache_get(index->tree, "subdir");
+	cl_assert(tree_cache);
+	cl_assert_equal_i(0, tree_cache->entry_count);
+}
+
 void test_index_cache__read_tree_children(void)
 {
 	git_index *index;