this commit adds support for differentiating between multiple different unique_usertypes without actually having to store type information. It does not include the ability to override a unique_usertype label for a specific type, but that might not prove necessary if differentiation remains possible with this methodology

Complete fixes #422 and addresses #423

sol/stack_check.hpp

@@ -429,8 +429,16 @@ namespace sol {
 					return true;
 				}
 				int metatableindex = lua_gettop(L);
-				if (stack_detail::check_metatable<detail::unique_usertype<T>>(L, metatableindex))
+				if (stack_detail::check_metatable<detail::unique_usertype<T>>(L, metatableindex)) {
-					return true;
+					void* memory = lua_touserdata(L, 1);
+					T** pointerpointer = static_cast<T**>(memory);
+					detail::unique_destructor& pdx = *static_cast<detail::unique_destructor*>(static_cast<void*>(pointerpointer + 1));
+					bool success = &detail::usertype_unique_alloc_destroy<T, X> == pdx;
+					if (!success) {
+						handler(L, index, type::userdata, indextype);
+					}
+					return success;
+				}
 				lua_pop(L, 1);
 				handler(L, index, type::userdata, indextype);
 				return false;

sol/stack_core.hpp

@@ -40,25 +40,26 @@ namespace sol {
 		template <typename T>
 		struct as_value_tag {};
 
-		using special_destruct_func = void(*)(void*);
+		using unique_destructor = void(*)(void*);
-
-		template <typename T, typename Real>
-		inline void special_destruct(void* memory) {
-			T** pointerpointer = static_cast<T**>(memory);
-			special_destruct_func* dx = static_cast<special_destruct_func*>(static_cast<void*>(pointerpointer + 1));
-			Real* target = static_cast<Real*>(static_cast<void*>(dx + 1));
-			target->~Real();
-		}
 
 		template <typename T>
 		inline int unique_destruct(lua_State* L) {
 			void* memory = lua_touserdata(L, 1);
 			T** pointerpointer = static_cast<T**>(memory);
-			special_destruct_func& dx = *static_cast<special_destruct_func*>(static_cast<void*>(pointerpointer + 1));
+			unique_destructor& dx = *static_cast<unique_destructor*>(static_cast<void*>(pointerpointer + 1));
 			(dx)(memory);
 			return 0;
 		}
 
+		template <typename T, typename Real>
+		inline void usertype_unique_alloc_destroy(void* memory) {
+			T** pointerpointer = static_cast<T**>(memory);
+			unique_destructor* dx = static_cast<unique_destructor*>(static_cast<void*>(pointerpointer + 1));
+			Real* target = static_cast<Real*>(static_cast<void*>(dx + 1));
+			std::allocator<Real> alloc;
+			alloc.destroy(target);
+		}
+
 		template <typename T>
 		inline int user_alloc_destroy(lua_State* L) {
 			void* rawdata = lua_touserdata(L, 1);

sol/stack_get.hpp

@@ -567,7 +567,7 @@ namespace sol {
 			static Real& get(lua_State* L, int index, record& tracking) {
 				tracking.use(1);
 				P** pref = static_cast<P**>(lua_touserdata(L, index));
-				detail::special_destruct_func* fx = static_cast<detail::special_destruct_func*>(static_cast<void*>(pref + 1));
+				detail::unique_destructor* fx = static_cast<detail::unique_destructor*>(static_cast<void*>(pref + 1));
 				Real* mem = static_cast<Real*>(static_cast<void*>(fx + 1));
 				return *mem;
 			}

sol/stack_push.hpp

@@ -153,10 +153,10 @@ namespace sol {
 
 			template <typename... Args>
 			static int push_deep(lua_State* L, Args&&... args) {
-				P** pref = static_cast<P**>(lua_newuserdata(L, sizeof(P*) + sizeof(detail::special_destruct_func) + sizeof(Real)));
+				P** pref = static_cast<P**>(lua_newuserdata(L, sizeof(P*) + sizeof(detail::unique_destructor) + sizeof(Real)));
-				detail::special_destruct_func* fx = static_cast<detail::special_destruct_func*>(static_cast<void*>(pref + 1));
+				detail::unique_destructor* fx = static_cast<detail::unique_destructor*>(static_cast<void*>(pref + 1));
 				Real* mem = static_cast<Real*>(static_cast<void*>(fx + 1));
-				*fx = detail::special_destruct<P, Real>;
+				*fx = detail::usertype_unique_alloc_destroy<P, Real>;
 				detail::default_construct::construct(mem, std::forward<Args>(args)...);
 				*pref = unique_usertype_traits<T>::get(*mem);
 				if (luaL_newmetatable(L, &usertype_traits<detail::unique_usertype<P>>::metatable()[0]) == 1) {

sol/usertype_metatable.hpp

@@ -746,8 +746,8 @@ namespace sol {
 				bool hasdestructor = !value_table.empty() && to_string(meta_function::garbage_collect) == value_table[lastreg - 1].name;
 				if (hasdestructor) {
 					ref_table[lastreg - 1] = { nullptr, nullptr };
-					unique_table[lastreg - 1] = { value_table[lastreg - 1].name, detail::unique_destruct<T> };
 				}
+				unique_table[lastreg - 1] = { value_table[lastreg - 1].name, detail::unique_destruct<T> };
 
 				// Now use um
 				const bool& mustindex = umc.mustindex;

test_functions.cpp

@@ -1137,35 +1137,88 @@ TEST_CASE("functions/set_function-already-wrapped", "setting a function returned
 }
 
 TEST_CASE("functions/unique-overloading", "make sure overloading can work with ptr vs. specifically asking for a unique usertype") {
-	sol::state lua;
+	struct test { 
-
+		int special_value = 17;
-	struct test { int special_value = 17; };
+		test() : special_value(17) {}
-	auto print_up_test = [](std::unique_ptr<test>& x) {
+		test(int special_value) : special_value(special_value) {}
-		REQUIRE(x->special_value == 17);
+	};
+	auto print_up_test = [](std::unique_ptr<test>& x) {
+		REQUIRE(x->special_value == 21);
+	};
+	auto print_sp_test = [](std::shared_ptr<test>& x) {
+		REQUIRE(x->special_value == 44);
 	};
-
 	auto print_ptr_test = [](test* x) {
 		REQUIRE(x->special_value == 17);
 	};
+	auto print_ref_test = [](test& x) {
+		bool is_any = x.special_value == 17
+			|| x.special_value == 21
+			|| x. special_value == 44;
+		REQUIRE(is_any);
+	};
+	using f_t = void(test&);
+	f_t* fptr = print_ref_test;
+	
+	std::unique_ptr<test> ut = std::make_unique<test>(17);
+	SECTION("working") {
+		sol::state lua;
 
-	lua.set_function("f", print_up_test);
+		lua.set_function("f", print_up_test);
-	lua.set_function("g", sol::overload(
+		lua.set_function("g", sol::overload(
-		std::ref(print_up_test),
+			std::move(print_sp_test),
-		print_ptr_test
+			print_up_test,
-	));
+			std::ref(print_ptr_test)
+		));
+		lua.set_function("h", std::ref(fptr));
 
-	lua["v1"] = std::make_unique<test>();
+		lua["v1"] = std::make_unique<test>(21);
-	lua["v2"] = test{};
+		lua["v2"] = std::make_shared<test>(44);
-	REQUIRE_NOTHROW([&]() {
+		lua["v3"] = test(17);
-		lua.script("g(v1)");
+		lua["v4"] = ut.get();
-	}());
+
-	REQUIRE_NOTHROW([&]() {
+		REQUIRE_NOTHROW([&]() {
-		lua.script("g(v2)");
+			lua.script("f(v1)");
-	}());
+			lua.script("g(v1)");
-	REQUIRE_NOTHROW([&]() {
+			lua.script("g(v2)");
-		lua.script("f(v1)");
+			lua.script("g(v3)");
-	}());
+			lua.script("g(v4)");
-	REQUIRE_THROWS([&]() {
+			lua.script("h(v1)");
-		lua.script("f(v2)");
+			lua.script("h(v2)");
-	}());
+			lua.script("h(v3)");
+			lua.script("h(v4)");
+		}());
+	};
+	// LuaJIT segfaults hard on some Linux machines
+	// and it breaks all the tests...
+	SECTION("throws-value") {
+		sol::state lua;
+
+		lua.set_function("f", print_up_test);
+		lua["v3"] = test(17);
+
+		REQUIRE_THROWS([&]() {
+			lua.script("f(v3)");
+		}());
+	};
+	SECTION("throws-shared_ptr") {
+		sol::state lua;
+
+		lua.set_function("f", print_up_test);
+		lua["v2"] = std::make_shared<test>(44);
+
+		REQUIRE_THROWS([&]() {
+			lua.script("f(v2)");
+		}());
+	};
+	SECTION("throws-ptr") {
+		sol::state lua;
+
+		lua.set_function("f", print_up_test);
+		lua["v4"] = ut.get();
+
+		REQUIRE_THROWS([&]() {
+			lua.script("f(v4)");
+		}());
+	};
 }