From 5f9c9278ffabd96082d46e025207732d8c4e6751 Mon Sep 17 00:00:00 2001
From: "Zezheng.Li" <Zezheng_Li@linux.alibaba.com>
Date: Wed, 11 Sep 2024 14:44:57 +0800
Subject: [PATCH] [struct_pack][fix] fix mod zero error when struct only
 contain compatible

---
 include/ylt/struct_pack/alignment.hpp     |  2 +-
 src/struct_pack/tests/test_compatible.cpp | 15 ++++++++++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/include/ylt/struct_pack/alignment.hpp b/include/ylt/struct_pack/alignment.hpp
index df0c801b3..432cdfcb9 100644
--- a/include/ylt/struct_pack/alignment.hpp
+++ b/include/ylt/struct_pack/alignment.hpp
@@ -160,7 +160,7 @@ constexpr auto calculate_padding_size() {
   std::array<std::size_t, struct_pack::members_count<T> + 1> padding_size{};
   std::size_t offset = 0;
   for_each<T, calculate_padding_size_impl>(offset, padding_size);
-  if (offset % align::alignment_v<T>) {
+  if (align::alignment_v < T >> 0 && offset % align::alignment_v<T>) {
     padding_size[struct_pack::members_count<T>] =
         align::alignment_v<T> - offset % align::alignment_v<T>;
   }
diff --git a/src/struct_pack/tests/test_compatible.cpp b/src/struct_pack/tests/test_compatible.cpp
index 59ae1abe9..1923e663d 100644
--- a/src/struct_pack/tests/test_compatible.cpp
+++ b/src/struct_pack/tests/test_compatible.cpp
@@ -3,6 +3,7 @@
 
 #include "doctest.h"
 #include "test_struct.hpp"
+#include "ylt/struct_pack/compatible.hpp"
 #include "ylt/struct_pack/endian_wrapper.hpp"
 
 using namespace struct_pack;
@@ -1307,4 +1308,16 @@ TEST_CASE("test nested trival_serialzable_obj_with_compatible") {
     CHECK(result.has_value());
     CHECK(test_equal(result.value(), a_v1));
   }
-}
\ No newline at end of file
+}
+
+struct only_compatible {
+  int i;
+  struct_pack::compatible<int> hi;
+};
+TEST_CASE("test only_compatible") {
+  only_compatible o{{0}};
+  auto buffer = struct_pack::serialize(o);
+  auto result = struct_pack::deserialize<only_compatible>(buffer);
+  CHECK(result.has_value());
+  CHECK(result->hi == o.hi);
+}