Fix #2608

Author: fredericDelaporte

src/NHibernate/Action/DelayedPostInsertIdentifier.cs

@@ -45,5 +45,10 @@ public override string ToString()
 		{
 			return string.Format("<delayed:{0}>", sequence);
 		}
+
+		/// <summary>
+		/// The actual identifier value that has been generated.
+		/// </summary>
+		public object ActualId { get; set; }
 	}
 }

src/NHibernate/Action/EntityInsertAction.cs

@@ -44,10 +44,16 @@ public override void Execute()
 
 			bool veto = PreInsert();
 
+			var isDelayed = false;
 			// Don't need to lock the cache here, since if someone
 			// else inserted the same pk first, the insert would fail
 			if (!veto)
 			{
+				if (id is DelayedPostInsertIdentifier delayed && delayed.ActualId != null)
+				{
+					isDelayed = true;
+					id = delayed.ActualId;
+				}
 				persister.Insert(id, State, instance, Session);
 
 				EntityEntry entry = Session.PersistenceContext.GetEntry(instance);
@@ -57,6 +63,10 @@ public override void Execute()
 				}
 
 				entry.PostInsert();
+				if (isDelayed)
+				{
+					Session.PersistenceContext.ReplaceDelayedEntityIdentityInsertKeys(entry.EntityKey, id);
+				}
 
 				if (persister.HasInsertGeneratedProperties)
 				{

src/NHibernate/Async/Action/EntityInsertAction.cs

@@ -40,10 +40,16 @@ public override async Task ExecuteAsync(CancellationToken cancellationToken)
 
 			bool veto = await (PreInsertAsync(cancellationToken)).ConfigureAwait(false);
 
+			var isDelayed = false;
 			// Don't need to lock the cache here, since if someone
 			// else inserted the same pk first, the insert would fail
 			if (!veto)
 			{
+				if (id is DelayedPostInsertIdentifier delayed && delayed.ActualId != null)
+				{
+					isDelayed = true;
+					id = delayed.ActualId;
+				}
 				await (persister.InsertAsync(id, State, instance, Session, cancellationToken)).ConfigureAwait(false);
 
 				EntityEntry entry = Session.PersistenceContext.GetEntry(instance);
@@ -53,6 +59,10 @@ public override async Task ExecuteAsync(CancellationToken cancellationToken)
 				}
 
 				entry.PostInsert();
+				if (isDelayed)
+				{
+					Session.PersistenceContext.ReplaceDelayedEntityIdentityInsertKeys(entry.EntityKey, id);
+				}
 
 				if (persister.HasInsertGeneratedProperties)
 				{

src/NHibernate/Async/Engine/StatefulPersistenceContext.cs

@@ -13,8 +13,8 @@
 using System.Collections.Generic;
 using System.Runtime.Serialization;
 using System.Security;
-using System.Security.Permissions;
 using System.Text;
+using NHibernate.Action;
 using NHibernate.Collection;
 using NHibernate.Engine.Loading;
 using NHibernate.Impl;

src/NHibernate/Async/Event/Default/AbstractSaveEventListener.cs

@@ -146,7 +146,8 @@ protected virtual async Task<object> PerformSaveAsync(object entity, object id,
 						throw new NonUniqueObjectException(id, persister.EntityName);
 					}
 				}
-				persister.SetIdentifier(entity, id);
+				if (!(id is DelayedPostInsertIdentifier))
+					persister.SetIdentifier(entity, id);
 			}
 			else
 			{

src/NHibernate/Engine/StatefulPersistenceContext.cs

@@ -3,8 +3,8 @@
 using System.Collections.Generic;
 using System.Runtime.Serialization;
 using System.Security;
-using System.Security.Permissions;
 using System.Text;
+using NHibernate.Action;
 using NHibernate.Collection;
 using NHibernate.Engine.Loading;
 using NHibernate.Impl;
@@ -1392,6 +1392,8 @@ public void ReplaceDelayedEntityIdentityInsertKeys(EntityKey oldKey, object gene
 			AddEntity(newKey, entity);
 			AddEntry(entity, oldEntry.Status, oldEntry.LoadedState, oldEntry.RowId, generatedId, oldEntry.Version,
 					 oldEntry.LockMode, oldEntry.ExistsInDatabase, oldEntry.Persister, oldEntry.IsBeingReplicated);
+			if (oldKey.Identifier is DelayedPostInsertIdentifier delayed)
+				delayed.ActualId = generatedId;
 		}
 
 		public bool IsLoadFinished

src/NHibernate/Event/Default/AbstractSaveEventListener.cs

@@ -173,7 +173,8 @@ protected virtual object PerformSave(object entity, object id, IEntityPersister
 						throw new NonUniqueObjectException(id, persister.EntityName);
 					}
 				}
-				persister.SetIdentifier(entity, id);
+				if (!(id is DelayedPostInsertIdentifier))
+					persister.SetIdentifier(entity, id);
 			}
 			else
 			{