Fixes issue 3622: ISession.Refresh updates initialized lazy properties

Author: Thomas Alken

src/NHibernate.Test/FetchLazyProperties/FetchLazyPropertiesFixture.cs

@@ -1075,6 +1075,41 @@ void AssertPersons(List<Person> results, bool fetched)
 				}
 			}
 		}
+		
+		[Test]
+		public void TestRefreshRemovesLazyLoadedProperties()
+		{
+			using (var outerSession = OpenSession())
+			{
+				const string query = "from Person fetch Image where Id = 1";
+				const string namePostFix = "_MODIFIED";
+				const int imageLength = 4711;
+				
+				Person outerPerson = outerSession.CreateQuery(query).UniqueResult<Person>();
+				
+				Assert.That(outerPerson.Name.EndsWith(namePostFix), Is.False); // Normal property 
+				Assert.That(outerPerson.Image.Length, Is.EqualTo(1)); // Lazy Property
+				
+				// Changing the properties of the person in a different sessions
+				using (var innerSession = OpenSession())
+				{
+					var transaction = innerSession.BeginTransaction();
+				
+					Person innerPerson = innerSession.CreateQuery(query).UniqueResult<Person>();
+					innerPerson.Image = new byte[imageLength];
+					innerPerson.Name += namePostFix;
+					innerSession.Update(innerPerson);
+					
+					transaction.Commit();
+				}
+				
+				// Refreshing the person in the outer session
+				outerSession.Refresh(outerPerson);
+				
+				Assert.That(outerPerson.Name.EndsWith(namePostFix), Is.True); // Value has changed
+				Assert.That(outerPerson.Image.Length, Is.EqualTo(imageLength)); // This is still the old value
+			}
+		}
 
 		private static Person GeneratePerson(int i, Person bestFriend)
 		{

src/NHibernate/Event/Default/DefaultRefreshEventListener.cs

@@ -97,7 +97,9 @@ public virtual void OnRefresh(RefreshEvent @event, IDictionary refreshedAlready)
 			}
 
 			EvictCachedCollections(persister, id, source.Factory);
-
+			
+			RefreshLazyProperties(persister, obj);
+			
 			// NH Different behavior : NH-1601
 			// At this point the entity need the real refresh, all elementes of collections are Refreshed,
 			// the collection state was evicted, but the PersistentCollection (in the entity state)
@@ -142,5 +144,20 @@ private void EvictCachedCollections(IType[] types, object id, ISessionFactoryImp
 				}
 			}
 		}
+		
+		private static void RefreshLazyProperties(IEntityPersister persister, object obj)
+		{
+			if (obj == null)
+				return;
+			
+			// TODO: InstrumentationMetadata needs to be in IPersister
+			var castedPersister = persister as AbstractEntityPersister;
+			if (castedPersister?.InstrumentationMetadata?.EnhancedForLazyLoading == true)
+			{
+				var interceptor = castedPersister.InstrumentationMetadata.ExtractInterceptor(obj);
+				// The list of initialized lazy fields have to be cleared in order to refresh them from the database.
+				interceptor?.ClearInitializedLazyFields();
+			}
+		}
 	}
 }

src/NHibernate/Intercept/AbstractFieldInterceptor.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Iesi.Collections.Generic;
 using NHibernate.Engine;
 using NHibernate.Persister.Entity;
@@ -21,7 +22,8 @@ public abstract class AbstractFieldInterceptor : IFieldInterceptor
 		private readonly HashSet<string> loadedUnwrapProxyFieldNames = new HashSet<string>();
 		private readonly string entityName;
 		private readonly System.Type mappedClass;
-
+		private readonly string[] originalUninitializedFields;
+		
 		[NonSerialized]
 		private bool initializing;
 		private bool isDirty;
@@ -34,6 +36,7 @@ protected internal AbstractFieldInterceptor(ISessionImplementor session, ISet<st
 			this.entityName = entityName;
 			this.mappedClass = mappedClass;
 			this.uninitializedFieldsReadOnly = uninitializedFields != null ? new ReadOnlySet<string>(uninitializedFields) : null;
+			this.originalUninitializedFields = uninitializedFields != null ? uninitializedFields.ToArray() : null;
 		}
 
 		#region IFieldInterceptor Members
@@ -209,5 +212,16 @@ public ISet<string> GetUninitializedFields()
 		{
 			return uninitializedFieldsReadOnly ?? CollectionHelper.EmptySet<string>();
 		}
+		
+		public void ClearInitializedLazyFields()
+		{
+			if (this.originalUninitializedFields == null) 
+				return;
+
+			foreach (var originalUninitializedField in this.originalUninitializedFields)
+			{
+				this.uninitializedFields.Add(originalUninitializedField);
+			}
+		}
 	}
 }

src/NHibernate/Intercept/IFieldInterceptor.cs

@@ -41,6 +41,8 @@ public interface IFieldInterceptor
 
 		/// <summary> Get the MappedClass (field container).</summary>
 		System.Type MappedClass { get; }
+		
+		void ClearInitializedLazyFields();
 	}
 
 	public static class FieldInterceptorExtensions