fixes trivial removes systems not triggering an event (#25)

Author: zaucy

ecsact/entt/trivial_system_impl.hh

@@ -67,6 +67,9 @@ void trivial_system_impl(
 	EachCallbackT&& each_callback = [](auto&, auto&, auto) {}
 ) {
 	using boost::mp11::mp_for_each;
+	using ecsact::entt::component_removed;
+	using ecsact::entt::detail::pending_remove;
+	using ecsact::entt::detail::temp_storage;
 
 	using caps_info = ecsact::system_capabilities_info<SystemT>;
 	using adds_components = typename caps_info::adds_components;
@@ -84,7 +87,18 @@ void trivial_system_impl(
 		});
 
 		mp_for_each<removes_components>([&]<typename C>(C) {
-			info.template remove_component<C>(entity);
+			info.registry.template emplace<pending_remove<C>>(entity);
+
+			if constexpr(!C::transient) {
+				info.registry.template emplace<component_removed<C>>(entity);
+
+				auto& temp = info.registry.template storage<temp_storage<C>>();
+				if(temp.contains(entity)) {
+					temp.get(entity).value = info.registry.template get<C>(entity);
+				} else {
+					temp.emplace(entity, info.registry.template get<C>(entity));
+				}
+			}
 		});
 
 		each_callback(view, assoc_views, entity);

runtime/test/runtime_test.cc

@@ -29,6 +29,14 @@ void runtime_test::OtherEntitySystem::impl(context& ctx) {
 void runtime_test::MakeAnother::impl(context& ctx) {
 }
 
+void runtime_test::TrivialRemove::impl(context& ctx) {
+	// This trivial remove should not even be required:
+	// SEE: https://github.com/ecsact-dev/ecsact_lang_cpp/issues/80
+	std::cerr << "TriviaLRemove impl called (SHOULD NOT HAPPEN)\n";
+	std::cerr.flush();
+	std::abort();
+}
+
 TEST(Core, CreateRegistry) {
 	auto reg_id = ecsact_create_registry("CreateRegistry");
 	EXPECT_NE(reg_id, ecsact_invalid_registry_id);
@@ -219,6 +227,45 @@ static void dynamic_impl(ecsact_system_execution_context* ctx) {
 	ecsact_system_execution_context_update(ctx, comp_id, &comp);
 }
 
+TEST(Core, TrivialRemoveEvent) {
+	auto reg_id = ecsact_create_registry("TrivialRemoveEvent");
+	auto entity = ecsact_create_entity(reg_id);
+
+	runtime_test::TrivialRemoveComponent comp{};
+	ecsact_add_component(
+		reg_id,
+		entity,
+		runtime_test::TrivialRemoveComponent::id,
+		&comp
+	);
+
+	ecsact_add_component(
+		reg_id,
+		entity,
+		runtime_test::WillRemoveTrivial::id,
+		nullptr
+	);
+
+	static bool                       event_happened = false;
+	ecsact_execution_events_collector ev_collector{};
+	ev_collector.remove_callback = //
+		[](
+			ecsact_event        event,
+			ecsact_entity_id    entity_id,
+			ecsact_component_id component_id,
+			const void*         component_data,
+			void*               callback_user_data
+		) {
+			event_happened = true;
+
+			EXPECT_EQ(component_id, runtime_test::TrivialRemoveComponent::id);
+		};
+
+	ecsact_execute_systems(reg_id, 1, nullptr, &ev_collector);
+
+	EXPECT_TRUE(event_happened);
+}
+
 TEST(Core, DynamicSystemImpl) {
 	ecsact::core::registry reg("DynamicSystemImpl");
 	auto                   entity = reg.create_entity();

runtime/test/runtime_test.ecsact

@@ -15,6 +15,13 @@ system SimpleSystem {
 	readwrite ComponentA;
 }
 
+component WillRemoveTrivial;
+component TrivialRemoveComponent { i32 example; }
+system TrivialRemove {
+  include WillRemoveTrivial;
+  removes TrivialRemoveComponent;
+}
+
 system OtherEntitySystem {
 	readwrite OtherEntityComponent with target {
 		readwrite ComponentA;