Skip zero size containers in protobuf.

L-LYR · Jan 15, 2022 · a3565e6 · a3565e6
1 parent cba44dc
commit a3565e6
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Showing 2 changed files with 33 additions and 5 deletions.
diff --git a/test/src/test_pb_protocol.cpp b/test/src/test_pb_protocol.cpp
@@ -495,4 +495,23 @@ TEST(test_pb_protocol, person_short)
     EXPECT_EQ(data, new_data);
 }
 
+TEST(test_pb_protocol, default_person_in_address_book)
+{
+    constexpr auto data = "\n\x00"_b;
+
+    address_book b;
+    zpp::bits::in{data, zpp::bits::no_size{}}(b).or_throw();
+
+    EXPECT_EQ(b.people.size(), 1u);
+    EXPECT_EQ(b.people[0].name, "");
+    EXPECT_EQ(b.people[0].id, 0);
+    EXPECT_EQ(b.people[0].email, "");
+    EXPECT_EQ(b.people[0].phones.size(), 0u);
+
+    std::array<std::byte, "0a021000"_decode_hex.size()> new_data;
+    zpp::bits::out{new_data, zpp::bits::no_size{}}(b).or_throw();
+
+    EXPECT_EQ(new_data, "0a021000"_decode_hex);
+}
+
 } // namespace test_pb_protocol
diff --git a/zpp_bits.h b/zpp_bits.h
@@ -4590,11 +4590,14 @@ struct pb
                                          std::byte>;
                              }) {
             constexpr auto tag = make_tag<tag_type, Index>();
-            if (auto result =
-                    archive(tag,
-                            varint{item.size() *
-                                   sizeof(typename type::value_type)},
-                            unsized(item));
+            auto size = item.size();
+            if (!size) [[unlikely]] {
+                return {};
+            }
+            if (auto result = archive(
+                    tag,
+                    varint{size * sizeof(typename type::value_type)},
+                    unsized(item));
                 failure(result)) [[unlikely]] {
                 return result;
             }
@@ -4610,6 +4613,9 @@ struct pb
                 size +=
                     varint_size<type::value_type::encoding>(element.value);
             }
+            if (!size) [[unlikely]] {
+                return {};
+            }
             if (auto result = archive(tag, varint{size}, unsized(item));
                 failure(result)) [[unlikely]] {
                 return result;
@@ -4626,6 +4632,9 @@ struct pb
             for (auto & element : item) {
                 size += varint_size(std::underlying_type_t<type>(element));
             }
+            if (!size) [[unlikely]] {
+                return {};
+            }
             if (auto result = archive(tag, varint{size}); failure(result))
                 [[unlikely]] {
                 return result;