registry: fixed a bug that affects late group initialization (close #440)

src/entt/entity/registry.hpp

@@ -1405,12 +1405,8 @@ public:
                 }
             } else {
                 // we cannot iterate backwards because we want to leave behind valid entities in case of owned types
-                std::for_each(std::get<0>(cpools).data(), std::get<0>(cpools).data() + std::get<0>(cpools).size(), [this, cpools, handler](const auto entity) {
-                    if(has<std::decay_t<Owned>..., std::decay_t<Get>...>(entity) && !any<Exclude...>(entity)) {
-                        if(const auto pos = handler->current; !(std::get<0>(cpools).index(entity) < ++handler->current)) {
-                            (std::get<pool_handler<std::decay_t<Owned>> &>(cpools).swap(std::get<pool_handler<std::decay_t<Owned>> &>(cpools).data()[pos], entity), ...);
-                        }
-                    }
+                std::for_each(std::get<0>(cpools).data(), std::get<0>(cpools).data() + std::get<0>(cpools).size(), [this, handler](const auto entity) {
+                    handler->template maybe_valid_if<std::tuple_element_t<0, std::tuple<std::decay_t<Owned>...>>>(*this, entity);
                 });
             }
         }

test/entt/entity/group.cpp

@@ -1121,7 +1121,7 @@ TEST(OwningGroup, SignalRace) {
     ASSERT_EQ(registry.group<int>(entt::get<double>).size(), 1u);
 }
 
-TEST(OwningGroup, AfterFact) {
+TEST(OwningGroup, StableLateInitialization) {
     entt::registry registry;
 
     for(std::size_t i{}; i < 30u; ++i) {
@@ -1133,3 +1133,20 @@ TEST(OwningGroup, AfterFact) {
     // thanks to @pgruenbacher for pointing out this corner case
     ASSERT_EQ((registry.group<int, char>().size()), 5u);
 }
+
+TEST(OwningGroup, PreventEarlyOptOut) {
+    entt::registry registry;
+
+    registry.assign<int>(registry.create(), 3);
+
+    const auto entity = registry.create();
+    registry.assign<char>(entity, 'c');
+    registry.assign<int>(entity, 2);
+
+    // thanks to @pgruenbacher for pointing out this corner case
+    registry.group<char, int>().each([entity](const auto entt, const auto &c, const auto &i) {
+        ASSERT_EQ(entity, entt);
+        ASSERT_EQ(c, 'c');
+        ASSERT_EQ(i, 2);
+    });
+}