EntityData.Version not serialized

Arch.Persistence.Tests/PersistenceTest.cs

@@ -158,8 +158,50 @@ public void JsonEntitySerialization()
 
         var newWorld = World.Create();
         var newEntity = _jsonSerializer.Deserialize(newWorld, bytes);
-        
+
         That(newEntity.Get<Transform>(), Is.EqualTo(entity.Get<Transform>()));
         That(newEntity.Get<MetaData>(), Is.EqualTo(entity.Get<MetaData>()));
     }
+
+    /// <summary>
+    ///     Checks if entities are alive after binary world deserialization.
+    ///     This verifies that EntityData.Version is correctly preserved.
+    /// </summary>
+    [Test]
+    public void BinaryWorldSerialization_EntitiesAreAlive()
+    {
+        var bytes = _binarySerializer.Serialize(_world);
+        var newWorld = _binarySerializer.Deserialize(bytes);
+
+        var newEntities = new Entity[newWorld.Size];
+        newWorld.GetEntities(new QueryDescription(), newEntities.AsSpan());
+
+        // All entities should be alive after deserialization
+        for (var index = 0; index < newEntities.Length; index++)
+        {
+            var entity = newEntities[index];
+            That(newWorld.IsAlive(entity), Is.True, $"Entity {entity.Id} with version {entity.Version} should be alive");
+        }
+    }
+
+    /// <summary>
+    ///     Checks if entities are alive after JSON world deserialization.
+    ///     This verifies that EntityData.Version is correctly preserved.
+    /// </summary>
+    [Test]
+    public void JsonWorldSerialization_EntitiesAreAlive()
+    {
+        var bytes = _jsonSerializer.Serialize(_world);
+        var newWorld = _jsonSerializer.Deserialize(bytes);
+
+        var newEntities = new Entity[newWorld.Size];
+        newWorld.GetEntities(new QueryDescription(), newEntities.AsSpan());
+
+        // All entities should be alive after deserialization
+        for (var index = 0; index < newEntities.Length; index++)
+        {
+            var entity = newEntities[index];
+            That(newWorld.IsAlive(entity), Is.True, $"Entity {entity.Id} with version {entity.Version} should be alive");
+        }
+    }
 }

Arch.Persistence/Binary.cs

@@ -269,17 +269,23 @@ public void Serialize(ref MessagePackWriter writer, EntityData value, MessagePac
 
         // Write entity index
         writer.WriteUInt32((uint)value.Slot.Index);
+
+        // Write version (required for IsAlive checks after deserialization)
+        writer.WriteInt32(value.Version);
     }
 
     /// <inheritdoc cref="IMessagePackFormatter{T}.Deserialize"/>
     public EntityData Deserialize(ref MessagePackReader reader, MessagePackSerializerOptions options)
     {
-        
+
         // Read chunk index and entity index
         var chunkIndex = reader.ReadUInt32();
         var entityIndex = reader.ReadUInt32();
 
-        return new EntityData(null!, new Slot((int)entityIndex, (int)chunkIndex), 0);
+        // Read version (required for IsAlive checks after deserialization)
+        var version = reader.ReadInt32();
+
+        return new EntityData(null!, new Slot((int)entityIndex, (int)chunkIndex), version);
     }
 }
 

Arch.Persistence/Json.cs

@@ -403,7 +403,7 @@ public partial class EntitySlotFormatter : IJsonFormatter<EntityData>
     public void Serialize(ref JsonWriter writer, EntityData value, IJsonFormatterResolver options)
     {
         writer.WriteBeginObject();
-        
+
         // Write chunk index
         writer.WritePropertyName("chunkIndex");
         writer.WriteUInt32((uint)value.Slot.ChunkIndex);
@@ -412,7 +412,12 @@ public void Serialize(ref JsonWriter writer, EntityData value, IJsonFormatterRes
         // Write entity index
         writer.WritePropertyName("index");
         writer.WriteUInt32((uint)value.Slot.Index);
-
+        writer.WriteValueSeparator();
+
+        // Write version (required for IsAlive checks after deserialization)
+        writer.WritePropertyName("version");
+        writer.WriteInt32(value.Version);
+
         writer.WriteEndObject();
     }
 
@@ -425,13 +430,18 @@ public EntityData Deserialize(ref JsonReader reader, IJsonFormatterResolver opti
         reader.ReadPropertyName();
         var chunkIndex = reader.ReadUInt32();
         reader.ReadIsValueSeparator();
-        
+
         // Read entity index
         reader.ReadPropertyName();
         var entityIndex = reader.ReadUInt32();
+        reader.ReadIsValueSeparator();
+
+        // Read version (required for IsAlive checks after deserialization)
+        reader.ReadPropertyName();
+        var version = reader.ReadInt32();
 
         reader.ReadIsEndObject();
-        return new EntityData(null!, new Slot((int)entityIndex, (int)chunkIndex), 0);
+        return new EntityData(null!, new Slot((int)entityIndex, (int)chunkIndex), version);
     }
 }