sparse_set: fix cross range-erase can break when using built-in iterators (close #913)

src/entt/entity/sparse_set.hpp

@@ -240,12 +240,14 @@ protected:
      */
     virtual void swap_and_pop(basic_iterator first, basic_iterator last) {
         for(; first != last; ++first) {
-            sparse_ref(packed.back()) = entity_traits::combine(static_cast<typename entity_traits::entity_type>(first.index()), entity_traits::to_integral(packed.back()));
-            const auto entt = std::exchange(packed[first.index()], packed.back());
+            auto &self = sparse_ref(*first);
+            const auto entt = entity_traits::to_entity(self);
+            sparse_ref(packed.back()) = entity_traits::combine(entt, entity_traits::to_integral(packed.back()));
+            packed[static_cast<size_type>(entt)] = packed.back();
             // unnecessary but it helps to detect nasty bugs
             ENTT_ASSERT((packed.back() = tombstone, true), "");
             // lazy self-assignment guard
-            sparse_ref(entt) = null;
+            self = null;
             packed.pop_back();
         }
     }
@@ -257,8 +259,8 @@ protected:
      */
     virtual void in_place_pop(basic_iterator first, basic_iterator last) {
         for(; first != last; ++first) {
-            sparse_ref(*first) = null;
-            packed[first.index()] = std::exchange(free_list, entity_traits::combine(static_cast<typename entity_traits::entity_type>(first.index()), entity_traits::reserved));
+            const auto entt = entity_traits::to_entity(std::exchange(sparse_ref(*first), null));
+            packed[static_cast<size_type>(entt)] = std::exchange(free_list, entity_traits::combine(entt, entity_traits::reserved));
         }
     }
 

test/entt/entity/sparse_set.cpp

@@ -428,6 +428,22 @@ TEST(SparseSetDeathTest, Erase) {
     ASSERT_DEATH(set.erase(entt::null), "");
 }
 
+TEST(SparseSet, CrossErase) {
+    using traits_type = entt::entt_traits<entt::entity>;
+
+    entt::sparse_set set;
+    entt::sparse_set other;
+    entt::entity entities[2u]{entt::entity{3}, entt::entity{42}};
+
+    set.insert(std::begin(entities), std::end(entities));
+    other.emplace(entities[1u]);
+    set.erase(other.begin(), other.end());
+
+    ASSERT_TRUE(set.contains(entities[0u]));
+    ASSERT_FALSE(set.contains(entities[1u]));
+    ASSERT_EQ(set.data()[0u], entities[0u]);
+}
+
 TEST(SparseSet, StableErase) {
     using traits_type = entt::entt_traits<entt::entity>;
 
@@ -552,6 +568,22 @@ TEST(SparseSetDeathTest, StableErase) {
     ASSERT_DEATH(set.erase(entt::null), "");
 }
 
+TEST(SparseSet, CrossStableErase) {
+    using traits_type = entt::entt_traits<entt::entity>;
+
+    entt::sparse_set set{entt::deletion_policy::in_place};
+    entt::sparse_set other{entt::deletion_policy::in_place};
+    entt::entity entities[2u]{entt::entity{3}, entt::entity{42}};
+
+    set.insert(std::begin(entities), std::end(entities));
+    other.emplace(entities[1u]);
+    set.erase(other.begin(), other.end());
+
+    ASSERT_TRUE(set.contains(entities[0u]));
+    ASSERT_FALSE(set.contains(entities[1u]));
+    ASSERT_EQ(set.data()[0u], entities[0u]);
+}
+
 TEST(SparseSet, Remove) {
     using traits_type = entt::entt_traits<entt::entity>;
 
@@ -609,6 +641,22 @@ TEST(SparseSet, Remove) {
     ASSERT_EQ(set.remove(entt::null), 0u);
 }
 
+TEST(SparseSet, CrossRemove) {
+    using traits_type = entt::entt_traits<entt::entity>;
+
+    entt::sparse_set set;
+    entt::sparse_set other;
+    entt::entity entities[2u]{entt::entity{3}, entt::entity{42}};
+
+    set.insert(std::begin(entities), std::end(entities));
+    other.emplace(entities[1u]);
+    set.remove(other.begin(), other.end());
+
+    ASSERT_TRUE(set.contains(entities[0u]));
+    ASSERT_FALSE(set.contains(entities[1u]));
+    ASSERT_EQ(set.data()[0u], entities[0u]);
+}
+
 TEST(SparseSet, StableRemove) {
     using traits_type = entt::entt_traits<entt::entity>;
 
@@ -739,6 +787,22 @@ TEST(SparseSet, StableRemove) {
     ASSERT_EQ(set.remove(entt::null), 0u);
 }
 
+TEST(SparseSet, CrossStableRemove) {
+    using traits_type = entt::entt_traits<entt::entity>;
+
+    entt::sparse_set set{entt::deletion_policy::in_place};
+    entt::sparse_set other{entt::deletion_policy::in_place};
+    entt::entity entities[2u]{entt::entity{3}, entt::entity{42}};
+
+    set.insert(std::begin(entities), std::end(entities));
+    other.emplace(entities[1u]);
+    set.remove(other.begin(), other.end());
+
+    ASSERT_TRUE(set.contains(entities[0u]));
+    ASSERT_FALSE(set.contains(entities[1u]));
+    ASSERT_EQ(set.data()[0u], entities[0u]);
+}
+
 TEST(SparseSet, Compact) {
     entt::sparse_set set{entt::deletion_policy::in_place};