From 48b7d0895afce6d19e791137748445d5f68beb78 Mon Sep 17 00:00:00 2001
From: jeffro256 <jeffro256@tutanota.com>
Date: Fri, 7 Jul 2023 16:45:38 -0500
Subject: [PATCH] epee binary: container can read from empty seq of any type

---
 tests/unit_tests/epee_serialization.cpp | 87 +++++++++++++++++++++++++
 1 file changed, 87 insertions(+)

diff --git a/tests/unit_tests/epee_serialization.cpp b/tests/unit_tests/epee_serialization.cpp
index 035f5e206..ecc26e971 100644
--- a/tests/unit_tests/epee_serialization.cpp
+++ b/tests/unit_tests/epee_serialization.cpp
@@ -29,8 +29,11 @@
 
 #include <cstdint>
 #include <gtest/gtest.h>
+#include <vector>
 
+#include "serialization/keyvalue_serialization.h"
 #include "storages/portable_storage.h"
+#include "storages/portable_storage_template_helper.h"
 #include "span.h"
 
 TEST(epee_binary, two_keys)
@@ -54,3 +57,87 @@ TEST(epee_binary, duplicate_key)
   epee::serialization::portable_storage storage{};
   EXPECT_FALSE(storage.load_from_binary(data));
 }
+
+namespace
+{
+struct ObjOfObjs
+{
+  std::vector<ObjOfObjs> x;
+
+  BEGIN_KV_SERIALIZE_MAP()
+    KV_SERIALIZE(x)
+  END_KV_SERIALIZE_MAP()
+};
+
+struct ObjOfInts
+{
+  std::list<int> x;
+
+  BEGIN_KV_SERIALIZE_MAP()
+    KV_SERIALIZE(x)
+  END_KV_SERIALIZE_MAP()
+};
+}
+
+TEST(epee_binary, any_empty_seq)
+{
+  // Test that any c++ sequence type (std::vector, std::list, etc) can deserialize without error
+  // from an *empty* epee binary array of any type. This property is useful for other projects who
+  // maintain code which serializes epee binary but don't know the type of arrays until runtime.
+  // Without any elements to actually serialize, they don't know what type code to use for arrays
+  // and should be able to choose a default typecode.
+
+  static constexpr const std::uint8_t data_empty_bool[] = {
+    0x01, 0x11, 0x01, 0x1, 0x01, 0x01, 0x02, 0x1, 0x1, 0x04, 0x01, 'x', 0x8B /*array of bools*/, 0x00 /*length 0*/
+  };
+
+  static constexpr const std::uint8_t data_empty_double[] = {
+    0x01, 0x11, 0x01, 0x1, 0x01, 0x01, 0x02, 0x1, 0x1, 0x04, 0x01, 'x', 0x89 /*array of doubles*/, 0x00 /*length 0*/
+  };
+
+  static constexpr const std::uint8_t data_empty_string[] = {
+    0x01, 0x11, 0x01, 0x1, 0x01, 0x01, 0x02, 0x1, 0x1, 0x04, 0x01, 'x', 0x8A /*array of strings*/, 0x00 /*length 0*/
+  };
+
+  static constexpr const std::uint8_t data_empty_int64[] = {
+    0x01, 0x11, 0x01, 0x1, 0x01, 0x01, 0x02, 0x1, 0x1, 0x04, 0x01, 'x', 0x81 /*array of int64s*/, 0x00 /*length 0*/
+  };
+
+  static constexpr const std::uint8_t data_empty_object[] = {
+    0x01, 0x11, 0x01, 0x1, 0x01, 0x01, 0x02, 0x1, 0x1, 0x04, 0x01, 'x', 0x8C /*array of objects*/, 0x00 /*length 0*/
+  };
+
+  ObjOfObjs o;
+
+  EXPECT_TRUE(epee::serialization::load_t_from_binary(o, epee::span<const std::uint8_t>(data_empty_bool)));
+  EXPECT_EQ(0, o.x.size());
+
+  EXPECT_TRUE(epee::serialization::load_t_from_binary(o, epee::span<const std::uint8_t>(data_empty_double)));
+  EXPECT_EQ(0, o.x.size());
+
+  EXPECT_TRUE(epee::serialization::load_t_from_binary(o, epee::span<const std::uint8_t>(data_empty_string)));
+  EXPECT_EQ(0, o.x.size());
+
+  EXPECT_TRUE(epee::serialization::load_t_from_binary(o, epee::span<const std::uint8_t>(data_empty_int64)));
+  EXPECT_EQ(0, o.x.size());
+
+  EXPECT_TRUE(epee::serialization::load_t_from_binary(o, epee::span<const std::uint8_t>(data_empty_object)));
+  EXPECT_EQ(0, o.x.size());
+
+  ObjOfInts i;
+
+  EXPECT_TRUE(epee::serialization::load_t_from_binary(i, epee::span<const std::uint8_t>(data_empty_bool)));
+  EXPECT_EQ(0, i.x.size());
+
+  EXPECT_TRUE(epee::serialization::load_t_from_binary(i, epee::span<const std::uint8_t>(data_empty_double)));
+  EXPECT_EQ(0, i.x.size());
+
+  EXPECT_TRUE(epee::serialization::load_t_from_binary(i, epee::span<const std::uint8_t>(data_empty_string)));
+  EXPECT_EQ(0, i.x.size());
+
+  EXPECT_TRUE(epee::serialization::load_t_from_binary(i, epee::span<const std::uint8_t>(data_empty_int64)));
+  EXPECT_EQ(0, i.x.size());
+
+  EXPECT_TRUE(epee::serialization::load_t_from_binary(i, epee::span<const std::uint8_t>(data_empty_object)));
+  EXPECT_EQ(0, i.x.size());
+}