fix crashes caused by interacting with associated components

Author: zaucy

ecsact/entt/runtime.hh

@@ -677,6 +677,11 @@ private:
 
 					auto& assoc_view = std::get<I>(assoc_views);
 					auto& assoc_view_itr = std::get<I>(assoc_views_itrs);
+					if(assoc_view.begin() == assoc_view.end()) {
+						missing_assoc_entities = true;
+						return;
+					}
+
 					assert(view.contains(entity));
 					auto& comp = view.template get<ComponentT>(entity);
 

runtime/test/runtime_test.cc

@@ -73,6 +73,14 @@ void runtime_test::AttackDamageWeakened::impl(context& ctx) {
 	// target_ctx.update(target_health);
 }
 
+void runtime_test::AddAssocTest::impl(context& ctx) {
+	auto other_entity = ctx.get<OtherEntityComponent>();
+
+	// Get Target other context from OtherEntityComponent
+	auto target_ctx = ctx._ctx.other(other_entity.target);
+	target_ctx.add(AddAssocTestComponent{.num = 10});
+}
+
 TEST(Core, CreateRegistry) {
 	auto reg_id = ecsact_create_registry("CreateRegistry");
 	EXPECT_NE(reg_id, ecsact_invalid_registry_id);
@@ -476,6 +484,40 @@ TEST(Core, ExecuteSystemsAssocActionOk) {
 	EXPECT_EQ(exec_err, ECSACT_EXEC_SYS_OK);
 }
 
+TEST(Core, AddAssocOk) {
+	ecsact_set_system_execution_impl(
+		ecsact_id_cast<ecsact_system_like_id>(runtime_test::AddAssocTest::id),
+		&runtime_test__AddAssocTest
+	);
+
+	auto reg = ecsact::core::registry("AddAssocOk");
+	auto test_entity1 = reg.create_entity();
+	reg.add_component(
+		test_entity1,
+		runtime_test::ComponentA{
+			.a = 42,
+		}
+	);
+
+	auto test_entity2 = reg.create_entity();
+	reg.add_component<runtime_test::AddAssocTestTag>(test_entity2);
+
+	auto options = ecsact_execution_options{};
+	auto test_action = runtime_test::AssocTestAction{
+		.assoc_entity = test_entity2,
+	};
+	auto test_action_c = ecsact_action{
+		.action_id = runtime_test::AssocTestAction::id,
+		.action_data = &test_action,
+	};
+
+	options.actions_length = 1;
+	options.actions = &test_action_c;
+	auto exec_err = ecsact_execute_systems(reg.id(), 1, &options, nullptr);
+
+	EXPECT_EQ(exec_err, ECSACT_EXEC_SYS_OK);
+}
+
 TEST(Core, AssociationEntityCorrectness) {
 	using runtime_test::AttackDamage;
 	using runtime_test::AttackDamageWeakened;

runtime/test/runtime_test.ecsact

@@ -61,6 +61,19 @@ action AssocTestAction {
 	adds OtherEntityComponent;
 }
 
+component AddAssocTestComponent {
+	i32 num;
+}
+
+component AddAssocTestTag;
+
+system AddAssocTest {
+	readwrite OtherEntityComponent with target {
+		include AddAssocTestTag;
+		adds AddAssocTestComponent;
+	}
+}
+
 system AttackDamage {
 	readwrite Attacking with target {
 		readwrite Health;