NH-3823 - Fix extra lazy PersistentGenericSet losing pending items on initialization

Fixes #1339

Co-authored-by: Alexander Zaytsev <[email protected]>

Author: martin-the-geek

src/NHibernate.Test/Async/Extralazy/ExtraLazyFixture.cs

@@ -1,4 +1,4 @@
-//------------------------------------------------------------------------------
+//------------------------------------------------------------------------------
 // <auto-generated>
 //     This code was generated by AsyncGenerator.
 //
@@ -306,5 +306,38 @@ public async Task SQLQueryAsync()
 				await (t.CommitAsync());
 			}
 		}
+
+		[Test]
+		public async Task AddToUninitializedSetWithLaterLazyLoadAsync()
+		{
+			User gavin;
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				gavin = new User("gavin", "secret");
+				var hia = new Document("HiA", "blah blah blah", gavin);
+				gavin.Documents.Add(hia);
+				await (s.PersistAsync(gavin));
+				await (t.CommitAsync());
+			}
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				gavin = await (s.GetAsync<User>("gavin"));
+				var hia2 = new Document("HiA2", "blah blah blah blah", gavin);
+				gavin.Documents.Add(hia2);
+
+				foreach (var _ in gavin.Documents)
+				{
+					//Force Iteration
+				}
+
+				Assert.That(gavin.Documents.Contains(hia2));
+				await (s.DeleteAsync(gavin));
+				await (t.CommitAsync());
+			}
+		}
 	}
 }

src/NHibernate.Test/Async/NHSpecificTest/NH1316/Fixture.cs

@@ -9,10 +9,8 @@
 
 
 using System;
-using System.Data.Common;
-using NUnit.Framework;
 using NHibernate.Dialect;
-
+using NUnit.Framework;
 
 namespace NHibernate.Test.NHSpecificTest.NH1316
 {

src/NHibernate.Test/Extralazy/ExtraLazyFixture.cs

@@ -295,5 +295,38 @@ public void SQLQuery()
 				t.Commit();
 			}
 		}
+
+		[Test]
+		public void AddToUninitializedSetWithLaterLazyLoad()
+		{
+			User gavin;
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				gavin = new User("gavin", "secret");
+				var hia = new Document("HiA", "blah blah blah", gavin);
+				gavin.Documents.Add(hia);
+				s.Persist(gavin);
+				t.Commit();
+			}
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				gavin = s.Get<User>("gavin");
+				var hia2 = new Document("HiA2", "blah blah blah blah", gavin);
+				gavin.Documents.Add(hia2);
+
+				foreach (var _ in gavin.Documents)
+				{
+					//Force Iteration
+				}
+
+				Assert.That(gavin.Documents.Contains(hia2));
+				s.Delete(gavin);
+				t.Commit();
+			}
+		}
 	}
 }

src/NHibernate/Collection/Generic/PersistentGenericSet.cs

@@ -191,13 +191,12 @@ public override void BeginRead()
 		/// </summary>
 		public override bool EndRead(ICollectionPersister persister)
 		{
-			foreach (T item in _tempList)
+			foreach (var item in _tempList)
 			{
 				WrappedSet.Add(item);
 			}
 			_tempList = null;
-			SetInitialized();
-			return true;
+			return base.EndRead(persister);
 		}
 
 		public override IEnumerable Entries(ICollectionPersister persister)