registry: drop ::empty (deprecated function)

src/entt/entity/registry.hpp

@@ -481,14 +481,6 @@ public:
         return entities.capacity();
     }
 
-    /**
-     * @brief Checks whether the registry is empty (no entities still in use).
-     * @return True if the registry is empty, false otherwise.
-     */
-    [[deprecated("use .storage<Entity>().in_use() instead")]] [[nodiscard]] bool empty() const {
-        return !alive();
-    }
-
     /**
      * @brief Direct access to the list of entities of a registry.
      *

src/entt/entity/snapshot.hpp

@@ -172,7 +172,9 @@ public:
     basic_snapshot_loader(registry_type &source) noexcept
         : reg{&source} {
         // restoring a snapshot as a whole requires a clean registry
-        ENTT_ASSERT(reg->empty(), "Registry must be empty");
+        for([[maybe_unused]] auto [id, elem]: source.storage()) {
+            ENTT_ASSERT(elem.empty(), "Registry must be empty");
+        }
     }
 
     /*! @brief Default move constructor. */

test/entt/entity/handle.cpp

@@ -216,7 +216,7 @@ TEST(BasicHandle, Lifetime) {
     handle->emplace<int>();
 
     ASSERT_FALSE(registry.storage<int>().empty());
-    ASSERT_FALSE(registry.empty());
+    ASSERT_NE(registry.storage<entt::entity>().in_use(), 0u);
 
     registry.each([handle](const auto e) {
         ASSERT_EQ(handle->entity(), e);
@@ -225,7 +225,7 @@ TEST(BasicHandle, Lifetime) {
     delete handle;
 
     ASSERT_FALSE(registry.storage<int>().empty());
-    ASSERT_FALSE(registry.empty());
+    ASSERT_NE(registry.storage<entt::entity>().in_use(), 0u);
 }
 
 TEST(BasicHandle, ImplicitConversions) {

test/entt/entity/registry.cpp

@@ -245,7 +245,7 @@ TEST(Registry, Functionalities) {
     ASSERT_EQ(registry.alive(), 0u);
     ASSERT_NO_FATAL_FAILURE(registry.reserve(42));
     ASSERT_EQ(registry.capacity(), 42u);
-    ASSERT_TRUE(registry.empty());
+    ASSERT_TRUE(registry.storage<entt::entity>().empty());
 
     ASSERT_EQ(registry.storage<int>().size(), 0u);
     ASSERT_EQ(registry.storage<char>().size(), 0u);
@@ -325,7 +325,7 @@ TEST(Registry, Functionalities) {
 
     ASSERT_EQ(registry.storage<entt::entity>().size(), 3u);
     ASSERT_EQ(registry.alive(), 3u);
-    ASSERT_FALSE(registry.empty());
+    ASSERT_NE(registry.storage<entt::entity>().in_use(), 0u);
 
     ASSERT_EQ(traits_type::to_version(e2), 0u);
     ASSERT_EQ(registry.current(e2), 0u);
@@ -339,13 +339,14 @@ TEST(Registry, Functionalities) {
 
     ASSERT_EQ(registry.storage<entt::entity>().size(), 3u);
     ASSERT_EQ(registry.alive(), 2u);
-    ASSERT_FALSE(registry.empty());
+    ASSERT_NE(registry.storage<entt::entity>().in_use(), 0u);
 
     ASSERT_NO_FATAL_FAILURE(registry.clear());
 
     ASSERT_EQ(registry.storage<entt::entity>().size(), 3u);
     ASSERT_EQ(registry.alive(), 0u);
-    ASSERT_TRUE(registry.empty());
+    ASSERT_EQ(registry.storage<entt::entity>().in_use(), 0u);
+    ASSERT_FALSE(registry.storage<entt::entity>().empty());
 
     const auto e3 = registry.create();
 
@@ -391,8 +392,8 @@ TEST(Registry, Constructors) {
     entt::registry registry;
     entt::registry other{42};
 
-    ASSERT_TRUE(registry.empty());
-    ASSERT_TRUE(other.empty());
+    ASSERT_TRUE(registry.storage<entt::entity>().empty());
+    ASSERT_TRUE(other.storage<entt::entity>().empty());
 
     ASSERT_EQ(registry.released(), 0u);
     ASSERT_EQ(other.released(), 0u);