Added fallbacks for back compatibility

Author: maca88

src/NHibernate/Async/Persister/Entity/IEntityPersister.cs

@@ -18,6 +18,8 @@
 using NHibernate.Type;
 using System.Collections;
 using System.Collections.Generic;
+using NHibernate.Intercept;
+using NHibernate.Util;
 
 namespace NHibernate.Persister.Entity
 {

src/NHibernate/Intercept/IFieldInterceptor.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using NHibernate.Engine;
+using NHibernate.Util;
 
 namespace NHibernate.Intercept
 {
@@ -30,7 +31,7 @@ public interface IFieldInterceptor
 
 		/// <summary> Intercept field set/get </summary>
 		// Since v5.3
-		[Obsolete("This method has no more usages and will be removed in a future version")]
+		[Obsolete("Please use 'Intercept(object target, string fieldName, object value, bool setter)' extension method instead")]
 		object Intercept(object target, string fieldName, object value);
 
 		/// <summary> Get the entity-name of the field DeclaringType.</summary>
@@ -42,16 +43,23 @@ public interface IFieldInterceptor
 
 	public static class FieldInterceptorExtensions
 	{
+		// 6.0 TODO: merge into IFieldInterceptor
 		internal static ISet<string> GetUninitializedLazyProperties(this IFieldInterceptor interceptor)
 		{
 			if (interceptor is AbstractFieldInterceptor fieldInterceptor)
 			{
 				return fieldInterceptor.GetUninitializedLazyProperties();
 			}
 
-			throw new NotSupportedException("GetUninitializedLazyProperties method is not supported.");
+			if (interceptor.IsInitialized)
+			{
+				return CollectionHelper.EmptySet<string>();
+			}
+
+			return null; // The called should use all lazy properties as the result
 		}
 
+		// 6.0 TODO: merge into IFieldInterceptor
 		public static object Intercept(this IFieldInterceptor interceptor, object target, string fieldName, object value, bool setter)
 		{
 			if (interceptor is AbstractFieldInterceptor fieldInterceptor)

src/NHibernate/Persister/Entity/AbstractEntityPersister.cs

@@ -4105,7 +4105,7 @@ public void AfterInitialize(object entity, bool lazyPropertiesAreUnfetched, ISes
 
 		internal ISet<string> GetUninitializedLazyProperties(object entity)
 		{
-			return EntityTuplizer.GetUninitializedLazyProperties(entity);
+			return EntityTuplizer.GetUninitializedLazyProperties(entity) ?? new HashSet<string>(lazyPropertyNames);
 		}
 
 		internal ISet<string> GetUninitializedLazyProperties(object[] state)

src/NHibernate/Persister/Entity/IEntityPersister.cs

@@ -8,6 +8,8 @@
 using NHibernate.Type;
 using System.Collections;
 using System.Collections.Generic;
+using NHibernate.Intercept;
+using NHibernate.Util;
 
 namespace NHibernate.Persister.Entity
 {
@@ -630,11 +632,26 @@ internal static ISet<string> GetUninitializedLazyProperties(this IEntityPersiste
 				return abstractEntityPersister.GetUninitializedLazyProperties(entity);
 			}
 
-			throw new InvalidOperationException($"{persister?.GetType()} does not support GetUninitializedLazyProperties method.");
+			if (!persister.HasUninitializedLazyProperties(entity))
+			{
+				return CollectionHelper.EmptySet<string>();
+			}
+
+			// Assume they are all uninitialized.
+			var result = new HashSet<string>();
+			for (var i = 0; i < persister.PropertyLaziness.Length; i++)
+			{
+				if (persister.PropertyLaziness[i])
+				{
+					result.Add(persister.PropertyNames[i]);
+				}
+			}
+
+			return result;
 		}
 
 		/// <summary>
-		/// Get uninitialized lazy properties from one row of a result set
+		/// Get uninitialized lazy properties from entity state
 		/// </summary>
 		//6.0 TODO: Merge into IEntityPersister
 		public static ISet<string> GetUninitializedLazyProperties(this IEntityPersister persister, object[] state)
@@ -644,7 +661,21 @@ public static ISet<string> GetUninitializedLazyProperties(this IEntityPersister
 				return abstractEntityPersister.GetUninitializedLazyProperties(state);
 			}
 
-			throw new InvalidOperationException($"{persister?.GetType()} does not support GetUninitializedProperties method.");
+			if (!persister.HasLazyProperties)
+			{
+				return CollectionHelper.EmptySet<string>();
+			}
+
+			var result = new HashSet<string>();
+			for (var i = 0; i < persister.PropertyLaziness.Length; i++)
+			{
+				if (persister.PropertyLaziness[i] && state[i] == LazyPropertyInitializer.UnfetchedProperty)
+				{
+					result.Add(persister.PropertyNames[i]);
+				}
+			}
+
+			return result;
 		}
 	}
 }

src/NHibernate/Tuple/Entity/IEntityTuplizer.cs

@@ -2,6 +2,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using NHibernate.Engine;
+using NHibernate.Util;
 
 namespace NHibernate.Tuple.Entity
 {
@@ -119,7 +120,7 @@ public interface IEntityTuplizer : ITuplizer
 		bool HasUninitializedLazyProperties(object entity);
 	}
 
-	internal static class EntityPersisterExtensions
+	internal static class EntityTuplizerExtensions
 	{
 		//6.0 TODO: Merge into IEntityTuplizer
 		internal static ISet<string> GetUninitializedLazyProperties(this IEntityTuplizer entityTuplizer, object entity)
@@ -128,8 +129,13 @@ internal static ISet<string> GetUninitializedLazyProperties(this IEntityTuplizer
 			{
 				return abstractEntityTuplizer.GetUninitializedLazyProperties(entity);
 			}
-			throw new NotSupportedException("GetUninitializedLazyProperties method is not supported.");
 
+			if (!entityTuplizer.HasUninitializedLazyProperties(entity))
+			{
+				return CollectionHelper.EmptySet<string>();
+			}
+
+			return null; // The called should use all lazy properties as the result
 		}
 	}
 }

src/NHibernate/Tuple/Entity/PocoEntityTuplizer.cs

@@ -286,7 +286,12 @@ internal override ISet<string> GetUninitializedLazyProperties(object entity)
 			}
 
 			var interceptor = FieldInterceptionHelper.ExtractFieldInterceptor(entity);
-			return interceptor?.GetUninitializedLazyProperties() ?? CollectionHelper.EmptySet<string>();
+			if (interceptor == null)
+			{
+				return CollectionHelper.EmptySet<string>();
+			}
+
+			return interceptor.GetUninitializedLazyProperties() ?? lazyPropertyNames;
 		}
 
 		public override bool IsLifecycleImplementor