storage: deprecate ::pack, use ::sort_as instead

src/entt/entity/sparse_set.hpp

@@ -1059,7 +1059,7 @@ public:
     void sort_as(It first, It last) {
         ENTT_ASSERT((mode != deletion_policy::in_place) || (head == traits_type::to_entity(null)), "Sorting with tombstones not allowed");
 
-        for(auto it = begin(); it.index() && first != last; ++first) {
+        for(auto it = begin(0); it.index() && first != last; ++first) {
             if(const auto curr = *first; contains(curr)) {
                 if(const auto entt = *it; entt != curr) {
                     // basic no-leak guarantee (with invalid state) if swapping throws

src/entt/entity/storage.hpp

@@ -1139,16 +1139,9 @@ public:
      * @return The number of elements within the newly created range.
      */
     template<typename It>
-    size_type pack(It first, It last) {
-        size_type len = base_type::free_list();
-
-        for(; first != last; ++first, --len) {
-            const auto pos = base_type::index(*first);
-            ENTT_ASSERT(pos < base_type::free_list(), "Invalid element");
-            base_type::swap_elements(base_type::data()[pos], base_type::data()[static_cast<size_type>(len - 1u)]);
-        }
-
-        return (base_type::free_list() - len);
+    [[deprecated("use sort_as instead")]] size_type pack(It first, It last) {
+        base_type::sort_as(first, last);
+        return static_cast<size_type>(std::distance(first, last));
     }
 
     /**

test/entt/entity/sparse_set.cpp

@@ -2013,11 +2013,12 @@ ENTT_DEBUG_TYPED_TEST(SparseSetDeathTest, SortAs) {
             ASSERT_DEATH(lhs.sort_as(rhs);, "");
         } break;
         case entt::deletion_policy::swap_only: {
-            entity_type entity[2u]{entity_type{3}, entity_type{42}};
+            entity_type entity[3u]{entity_type{3}, entity_type{42}, entity_type{9}};
 
             lhs.push(std::begin(entity), std::end(entity));
             rhs.push(std::rbegin(entity), std::rend(entity));
-            lhs.erase(entity[1u]);
+            lhs.erase(entity[0u]);
+            lhs.bump(entity[0u]);
 
             ASSERT_DEATH(lhs.sort_as(rhs);, "");
         } break;