fix: Extensions.DeepCopy broken for classes containing AttributeLayeredValues

while deserializing a hashset containing AttributeLayeredValues AttributeLayeredValues.ContentEquals is broken because the content isnt deserialised which results in all values of the Hashset being collapsed to one.

Author: firo222

src/FluentNHibernate.Testing/DomainModel/Mapping/CompositeIdentityPartTester.cs

@@ -159,6 +159,26 @@ public void MixedKeyPropertyAndManyToOneOrdering()
                 .RootElement.Element("class/composite-id/*[2]")
                     .HasName("key-property");
         }
+        
+        [Test]
+        public void CompositeIdWithSubclass()
+        {
+            new MappingTester<CompIdTarget>()
+                .SubClassMapping<ComIdSubclass>(s =>
+                {
+                    s.Table("subclasstable");
+                    s.KeyColumn("subclass_longId");
+                    s.KeyColumn("subclass_nullablelongId");
+                })
+                .ForMapping(c => c.CompositeId()
+                    .KeyProperty(x => x.LongId)
+                    .KeyProperty(x => x.NullableLongId))
+                .Element("class/joined-subclass/key/*[1]")
+                    .Exists().HasName("column").HasAttribute("name", "subclass_longId")
+                .RootElement.Element("class/joined-subclass/key/*[2]")
+                    .Exists().HasName("column").HasAttribute("name", "subclass_nullablelongId")
+                ;
+        }
 
         public class CompIdTarget
         {
@@ -183,5 +203,10 @@ public class ComponentKey
             public virtual int KeyCol1 { get; set; }
             public virtual int KeyCol2 { get; set; }
         }
+        
+        public class ComIdSubclass : CompIdTarget
+        {
+            
+        }
     }
 }

src/FluentNHibernate/MappingModel/Collections/AttributeLayeredValues.cs

@@ -1,14 +1,27 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.Serialization;
 
 namespace FluentNHibernate.MappingModel.Collections
 {
     [Serializable]
-    public class AttributeLayeredValues
+    public class AttributeLayeredValues : ISerializable
     {
-        readonly Dictionary<string, LayeredValues> inner = new Dictionary<string, LayeredValues>();
+        readonly Dictionary<string, LayeredValues> inner;
 
+        public AttributeLayeredValues()
+        {
+            inner = new Dictionary<string, LayeredValues>();
+        }
+
+        public AttributeLayeredValues(SerializationInfo info, StreamingContext context)
+        {
+            inner = (Dictionary<string, LayeredValues>)info
+                .GetValue("inner", typeof(Dictionary<string, LayeredValues>));
+            inner.OnDeserialization(this);
+        }
+        
         public LayeredValues this[string attribute]
         {
             get
@@ -90,5 +103,10 @@ public override int GetHashCode()
 
             return hashCode;
         }
+        
+        public void GetObjectData(SerializationInfo info, StreamingContext context)
+        {
+            info.AddValue("inner", inner);
+        }
     }
 }