storage/registry: batch add default-constructs the component

src/entt/entity/registry.hpp

@@ -73,10 +73,10 @@ class basic_registry {
             return this->get(entt);
         }
 
-        template<typename It, typename... Args>
+        template<typename It>
         std::enable_if_t<std::is_same_v<typename std::iterator_traits<It>::value_type, Entity>, typename storage<Entity, Component>::reverse_iterator_type>
-        assign(basic_registry &owner, It first, It last, Args &&... args) {
-            auto it = this->construct(first, last, std::forward<Args>(args)...);
+        assign(basic_registry &owner, It first, It last) {
+            auto it = this->construct(first, last);
             std::for_each(first, last, [this, &owner](const auto entt) { construction.publish(entt, owner); });
             return it;
         }
@@ -633,21 +633,21 @@ public:
     /**
      * @brief Assigns each entity in a range the given component.
      *
+     * The component type must be at least move and default insertable.
+     *
      * @sa assign
      *
      * @tparam Component Type of component to create.
      * @tparam It Type of input iterator.
-     * @tparam Args Types of arguments to use to construct the components.
      * @param first An iterator to the first element of the range of entities.
      * @param last An iterator past the last element of the range of entities.
-     * @param args Parameters to use to initialize the components.
      * @return An iterator to the list of components just created.
      */
-    template<typename Component, typename It, typename... Args>
+    template<typename Component, typename It>
     std::enable_if_t<std::is_same_v<typename std::iterator_traits<It>::value_type, entity_type>, typename pool_handler<Component>::reverse_iterator_type>
-    assign(It first, It last, Args &&... args) {
+    assign(It first, It last) {
         ENTT_ASSERT(std::all_of(first, last, [this](const auto entity) { return valid(entity); }));
-        return assure<Component>().assign(*this, first, last, std::forward<Args>(args)...);
+        return assure<Component>().assign(*this, first, last);
     }
 
     /**

src/entt/entity/storage.hpp

@@ -332,10 +332,9 @@ public:
 
     /**
      * @brief Assigns one or more entities to a storage and default constructs
-     * or copy constructs their objects.
+     * their objects.
      *
-     * The object type must be at least move and default insertable if no
-     * arguments are provided, move and copy insertable otherwise.
+     * The object type must be at least move and default insertable.
      *
      * @warning
      * Attempting to assign an entity that already belongs to the storage
@@ -344,17 +343,15 @@ public:
      * storage already contains the given entity.
      *
      * @tparam It Type of forward iterator.
-     * @tparam Args Types of arguments to use to construct the object.
      * @param first An iterator to the first element of the range of entities.
      * @param last An iterator past the last element of the range of entities.
-     * @param args Parameters to use to construct an object for the entities.
      * @return An iterator to the list of instances just created and sorted the
      * same of the entities.
      */
-    template<typename It, typename... Args>
+    template<typename It>
     std::enable_if_t<std::is_same_v<typename std::iterator_traits<It>::value_type, entity_type>, reverse_iterator_type>
-    construct(It first, It last, Args &&... args) {
-        instances.insert(instances.end(), std::distance(first, last), object_type{std::forward<Args>(args)...});
+    construct(It first, It last) {
+        instances.insert(instances.end(), std::distance(first, last), object_type{});
         // entity goes after component in case constructor throws
         underlying_type::construct(first, last);
         return std::make_reverse_iterator(begin() + std::distance(first, last));
@@ -656,8 +653,6 @@ public:
     /**
      * @brief Assigns an entity to a storage and constructs its object.
      *
-     * The object type must be at least copy constructible.
-     *
      * @warning
      * Attempting to use an entity that already belongs to the storage results
      * in undefined behavior.<br/>
@@ -666,21 +661,15 @@ public:
      *
      * @tparam Args Types of arguments to use to construct the object.
      * @param entt A valid entity identifier.
-     * @param args Parameters to use to construct an object for the entity.
      */
     template<typename... Args>
-    void construct(const entity_type entt, Args &&... args) {
-        [[maybe_unused]] object_type instance{std::forward<Args>(args)...};
-        // entity goes after component in case constructor throws
+    void construct(const entity_type entt, Args &&...) {
         underlying_type::construct(entt);
     }
 
     /**
      * @brief Assigns one or more entities to a storage.
      *
-     * The object type must be at least default constructible if no arguments
-     * are provided.
-     *
      * @warning
      * Attempting to assign an entity that already belongs to the storage
      * results in undefined behavior.<br/>
@@ -688,18 +677,14 @@ public:
      * storage already contains the given entity.
      *
      * @tparam It Type of forward iterator.
-     * @tparam Args Types of arguments to use to construct the object.
      * @param first An iterator to the first element of the range of entities.
      * @param last An iterator past the last element of the range of entities.
-     * @param args Parameters to use to construct an object for the entities.
      * @return An iterator to the list of instances just created and sorted the
      * same of the entities.
      */
-    template<typename It, typename... Args>
+    template<typename It>
     std::enable_if_t<std::is_same_v<typename std::iterator_traits<It>::value_type, entity_type>, reverse_iterator_type>
-    construct(It first, It last, Args &&... args) {
-        [[maybe_unused]] object_type instance{std::forward<Args>(args)...};
-        // entity goes after component in case constructor throws
+    construct(It first, It last) {
         underlying_type::construct(first, last);
         return std::make_reverse_iterator(begin() + std::distance(first, last));
     }

test/entt/entity/storage.cpp

@@ -117,29 +117,6 @@ TEST(Storage, BatchAdd) {
     ASSERT_EQ(pool.get(entities[1]), 2);
 }
 
-TEST(Storage, BatchAddByCopy) {
-    entt::storage<entt::entity, int> pool;
-    entt::entity entities[2];
-
-    entities[0] = entt::entity{3};
-    entities[1] = entt::entity{42};
-    auto it = pool.construct(std::begin(entities), std::end(entities), 3);
-
-    ASSERT_TRUE(pool.has(entities[0]));
-    ASSERT_TRUE(pool.has(entities[1]));
-
-    ASSERT_FALSE(pool.empty());
-    ASSERT_EQ(pool.size(), 2u);
-    ASSERT_EQ(pool.get(entities[0]), 3);
-    ASSERT_EQ(pool.get(entities[1]), 3);
-
-    it[0] = 1;
-    it[1] = 2;
-
-    ASSERT_EQ(pool.get(entities[0]), 1);
-    ASSERT_EQ(pool.get(entities[1]), 2);
-}
-
 TEST(Storage, BatchAddEmptyType) {
     entt::storage<entt::entity, empty_type> pool;
     entt::entity entities[2];