Fix has_tag for variant custom tag

morganstanley · Jun 24, 2022 · e94cccc · e94cccc
1 parent 7bb21fc
commit e94cccc
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Showing 2 changed files with 15 additions and 0 deletions.
diff --git a/include/binlog/adapt_stdvariant.hpp b/include/binlog/adapt_stdvariant.hpp
@@ -55,6 +55,13 @@ struct CustomSerializer<std::variant<T...>>
 template <typename... T>
 struct CustomTag<std::variant<T...>>
 {
+  // Make this type not-constructible, if some Tag<T> is not constructible
+  std::conditional_t<
+    detail::conjunction<detail::has_tag<T>...>::value,
+    std::true_type,
+    mserialize::detail::BuiltinTag<void>
+  > tag_guard;
+
   static constexpr auto tag_string()
   {
     return cx_strcat(

diff --git a/test/integration/LoggingVariants.cpp b/test/integration/LoggingVariants.cpp
@@ -91,3 +91,11 @@ int main()
 
   binlog::consume(std::cout);
 }
+
+struct Adapted {};
+BINLOG_ADAPT_STRUCT(Adapted)
+
+struct NotAdapted {};
+
+static_assert(mserialize::detail::has_tag<std::variant<Adapted>>::value, "");
+static_assert(!mserialize::detail::has_tag<std::variant<NotAdapted>>::value, "");