Cleanup and test template specializations

Author: wravery

include/graphqlservice/GraphQLService.h

@@ -591,15 +591,14 @@ enum class TypeModifier
 	List,
 };
 
+// Used by ModifiedArgument to special-case an innermost nullable INPUT_OBJECT type.
+template <TypeModifier... Other>
+constexpr bool onlyNoneModifiers = (... && (Other == TypeModifier::None));
+
+// Specialized as true for all INPUT_OBJECT types.
 template <typename Type>
 constexpr bool isInputType = false;
 
-template <TypeModifier Modifier>
-constexpr bool isNoneModifier = (Modifier == TypeModifier::None);
-
-template <TypeModifier... Other>
-constexpr bool trailingNoneModifiers = (... && isNoneModifer<Other>);
-
 // Extract individual arguments with chained type modifiers which add nullable or list wrappers.
 // If the argument is not optional, use require and let it throw a schema_exception when the
 // argument is missing or not the correct type. If it's optional, use find and check the second
@@ -613,7 +612,7 @@ struct ModifiedArgument
 	{
 		// Peel off modifiers until we get to the underlying type.
 		using type = typename std::conditional_t<TypeModifier::Nullable == Modifier,
-			typename std::conditional_t<isInputType<U> && trailingNoneModifiers<Other...>,
+			typename std::conditional_t<isInputType<U> && onlyNoneModifiers<Other...>,
 				std::unique_ptr<U>, std::optional<typename ArgumentTraits<U, Other...>::type>>,
 			typename std::conditional_t<TypeModifier::List == Modifier,
 				std::vector<typename ArgumentTraits<U, Other...>::type>, U>>;
@@ -693,7 +692,7 @@ struct ModifiedArgument
 
 		auto result = require<Other...>(name, arguments);
 
-		if constexpr (isInputType<Type> && trailingNoneModifiers<Other...>)
+		if constexpr (isInputType<Type> && onlyNoneModifiers<Other...>)
 		{
 			return std::make_unique<decltype(result)>(std::move(result));
 		}

test/ArgumentTests.cpp

@@ -331,3 +331,22 @@ TEST(ArgumentsCase, FindArgumentEmptyTemplateArgs)
 	ASSERT_EQ(response::Type::String, actual.first.type()) << "should parse the object";
 	ASSERT_EQ("foobar", actual.first.get<std::string>()) << "should match the value";
 }
+
+TEST(ArgumentsCase, OnlyNoneModifiers)
+{
+	constexpr bool emptyModifiers = service::onlyNoneModifiers<>;
+	constexpr bool threeNone = service::onlyNoneModifiers<service::TypeModifier::None,
+		service::TypeModifier::None,
+		service::TypeModifier::None>;
+	constexpr bool firtNullable = service::onlyNoneModifiers<service::TypeModifier::Nullable,
+		service::TypeModifier::None,
+		service::TypeModifier::None>;
+	constexpr bool middleList = service::onlyNoneModifiers<service::TypeModifier::None,
+		service::TypeModifier::List,
+		service::TypeModifier::None>;
+
+	ASSERT_TRUE(emptyModifiers) << "onlyNoneModifiers<> is true";
+	ASSERT_TRUE(threeNone) << "onlyNoneModifiers<None, None, None> is true";
+	ASSERT_FALSE(firtNullable) << "onlyNoneModifiers<Nullable, None, None> is false";
+	ASSERT_FALSE(middleList) << "onlyNoneModifiers<None, List, None> is false";
+}