Fix caching linq query with ThenFetchMany

src/NHibernate.Test/Async/NHSpecificTest/GH2559/FixtureByCode.cs

@@ -0,0 +1,156 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by AsyncGenerator.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+
+using System.Linq;
+using NHibernate.Cfg.MappingSchema;
+using NHibernate.Linq;
+using NHibernate.Mapping.ByCode;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.GH2559
+{
+	using System.Threading.Tasks;
+	[TestFixture]
+	public class ByCodeFixtureAsync : TestCaseMappingByCode
+	{
+		protected override HbmMapping GetMappings()
+		{
+			var mapper = new ModelMapper();
+			mapper.Class<Person>(rc =>
+			{
+				rc.Id(x => x.Id, m => m.Generator(Generators.Guid));
+				rc.Property(x => x.Name);
+				rc.Property(x => x.Age);
+				rc.Set(
+					x => x.Children,
+					colMap =>
+					{
+						colMap.Inverse(true);
+						colMap.Cascade(Mapping.ByCode.Cascade.DeleteOrphans);
+						colMap.Cache(c => c.Usage(CacheUsage.ReadWrite));
+					},
+					rel => rel.OneToMany());
+				rc.Set(
+					x => x.Cars,
+					colMap =>
+					{
+						colMap.Inverse(true);
+						colMap.Cascade(Mapping.ByCode.Cascade.DeleteOrphans);
+						colMap.Cache(c => c.Usage(CacheUsage.ReadWrite));
+					},
+					rel => rel.OneToMany());
+				rc.Cache(c => c.Usage(CacheUsage.ReadWrite));
+			});
+			mapper.Class<Child>(ch =>
+			{
+				ch.Id(x => x.Id, m => m.Generator(Generators.Guid));
+				ch.Property(x => x.Name);
+				ch.ManyToOne(c => c.Parent);
+
+				ch.Set(
+					x => x.Pets,
+					colMap =>
+					{
+						colMap.Inverse(true);
+						colMap.Cascade(Mapping.ByCode.Cascade.DeleteOrphans);
+						colMap.Cache(c => c.Usage(CacheUsage.ReadWrite));
+					},
+					rel => rel.OneToMany());
+
+				ch.Cache(c => c.Usage(CacheUsage.ReadWrite));
+			});
+			mapper.Class<Pet>(ch =>
+			{
+				ch.Id(x => x.Id, m => m.Generator(Generators.Guid));
+				ch.Property(x => x.Name);
+				ch.ManyToOne(c => c.Owner);
+
+				ch.Cache(c => c.Usage(CacheUsage.ReadWrite));
+			});
+			mapper.Class<Car>(ch =>
+			{
+				ch.Id(x => x.Id, m => m.Generator(Generators.Guid));
+				ch.Property(x => x.Name);
+				ch.ManyToOne(c => c.Owner);
+
+				ch.Cache(c => c.Usage(CacheUsage.ReadWrite));
+			});
+
+			return mapper.CompileMappingForAllExplicitlyAddedEntities();
+		}
+
+		protected override void OnSetUp()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				var person = new Person { Name = "Person 1", Age = 18 };
+
+				var car1 = new Car { Name = "Car1", Owner = person };
+				var car2 = new Car { Name = "Car2", Owner = person };
+				session.Save(car1);
+				session.Save(car2);
+
+				session.Save(person);
+				transaction.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				session.CreateQuery("delete from Pet").ExecuteUpdate();
+				session.CreateQuery("delete from Child").ExecuteUpdate();
+				session.CreateQuery("delete from Car").ExecuteUpdate();
+				session.CreateQuery("delete from Person").ExecuteUpdate();
+				transaction.Commit();
+			}
+		}
+
+		[Test]
+		public async Task TestQueryCachingWithThenFetchManyAsync()
+		{
+			Person dbPerson;
+			Person cachePerson;
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				var query =
+					session
+						.Query<Person>()
+						.FetchMany(p => p.Children)
+							.ThenFetchMany(ch => ch.Pets)
+						.FetchMany(p => p.Cars) as IQueryable<Person>;
+
+				query = query.WithOptions(opt =>
+					opt.SetCacheable(true)
+						.SetCacheMode(CacheMode.Normal)
+						.SetCacheRegion("Long_Cache"));
+
+				dbPerson = (await (query.ToListAsync())).First(); // First time the result will be cached
+				cachePerson = (await (query.ToListAsync())).First();
+
+				await (transaction.CommitAsync());
+			}
+
+			Assert.That(NHibernateUtil.IsInitialized(dbPerson.Cars), Is.True);
+			Assert.That(NHibernateUtil.IsInitialized(cachePerson.Cars), Is.True);
+			Assert.That(dbPerson.Cars, Has.Count.EqualTo(2));
+			Assert.That(cachePerson.Cars, Has.Count.EqualTo(2));
+
+			Assert.That(NHibernateUtil.IsInitialized(dbPerson.Children), Is.True);
+			Assert.That(NHibernateUtil.IsInitialized(cachePerson.Children), Is.True);
+			Assert.That(dbPerson.Children, Has.Count.EqualTo(0));
+			Assert.That(cachePerson.Children, Has.Count.EqualTo(0));
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH2559/Car.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace NHibernate.Test.NHSpecificTest.GH2559
+{
+	public class Car
+	{
+		public virtual Guid Id { get; set; }
+		public virtual string Name { get; set; }
+
+		public virtual Person Owner { get; set; }
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH2559/Child.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+
+namespace NHibernate.Test.NHSpecificTest.GH2559
+{
+	public class Child
+	{
+		public virtual Guid Id { get; set; }
+		public virtual string Name { get; set; }
+
+		public virtual Person Parent { get; set; }
+
+		public virtual ISet<Pet> Pets
+		{
+			get => _pets ?? (_pets = new HashSet<Pet>());
+			set => _pets = value;
+		}
+		private ISet<Pet> _pets;
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH2559/FixtureByCode.cs

@@ -0,0 +1,145 @@
+using System.Linq;
+using NHibernate.Cfg.MappingSchema;
+using NHibernate.Linq;
+using NHibernate.Mapping.ByCode;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.GH2559
+{
+	[TestFixture]
+	public class ByCodeFixture : TestCaseMappingByCode
+	{
+		protected override HbmMapping GetMappings()
+		{
+			var mapper = new ModelMapper();
+			mapper.Class<Person>(rc =>
+			{
+				rc.Id(x => x.Id, m => m.Generator(Generators.Guid));
+				rc.Property(x => x.Name);
+				rc.Property(x => x.Age);
+				rc.Set(
+					x => x.Children,
+					colMap =>
+					{
+						colMap.Inverse(true);
+						colMap.Cascade(Mapping.ByCode.Cascade.DeleteOrphans);
+						colMap.Cache(c => c.Usage(CacheUsage.ReadWrite));
+					},
+					rel => rel.OneToMany());
+				rc.Set(
+					x => x.Cars,
+					colMap =>
+					{
+						colMap.Inverse(true);
+						colMap.Cascade(Mapping.ByCode.Cascade.DeleteOrphans);
+						colMap.Cache(c => c.Usage(CacheUsage.ReadWrite));
+					},
+					rel => rel.OneToMany());
+				rc.Cache(c => c.Usage(CacheUsage.ReadWrite));
+			});
+			mapper.Class<Child>(ch =>
+			{
+				ch.Id(x => x.Id, m => m.Generator(Generators.Guid));
+				ch.Property(x => x.Name);
+				ch.ManyToOne(c => c.Parent);
+
+				ch.Set(
+					x => x.Pets,
+					colMap =>
+					{
+						colMap.Inverse(true);
+						colMap.Cascade(Mapping.ByCode.Cascade.DeleteOrphans);
+						colMap.Cache(c => c.Usage(CacheUsage.ReadWrite));
+					},
+					rel => rel.OneToMany());
+
+				ch.Cache(c => c.Usage(CacheUsage.ReadWrite));
+			});
+			mapper.Class<Pet>(ch =>
+			{
+				ch.Id(x => x.Id, m => m.Generator(Generators.Guid));
+				ch.Property(x => x.Name);
+				ch.ManyToOne(c => c.Owner);
+
+				ch.Cache(c => c.Usage(CacheUsage.ReadWrite));
+			});
+			mapper.Class<Car>(ch =>
+			{
+				ch.Id(x => x.Id, m => m.Generator(Generators.Guid));
+				ch.Property(x => x.Name);
+				ch.ManyToOne(c => c.Owner);
+
+				ch.Cache(c => c.Usage(CacheUsage.ReadWrite));
+			});
+
+			return mapper.CompileMappingForAllExplicitlyAddedEntities();
+		}
+
+		protected override void OnSetUp()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				var person = new Person { Name = "Person 1", Age = 18 };
+
+				var car1 = new Car { Name = "Car1", Owner = person };
+				var car2 = new Car { Name = "Car2", Owner = person };
+				session.Save(car1);
+				session.Save(car2);
+
+				session.Save(person);
+				transaction.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				session.CreateQuery("delete from Pet").ExecuteUpdate();
+				session.CreateQuery("delete from Child").ExecuteUpdate();
+				session.CreateQuery("delete from Car").ExecuteUpdate();
+				session.CreateQuery("delete from Person").ExecuteUpdate();
+				transaction.Commit();
+			}
+		}
+
+		[Test]
+		public void TestQueryCachingWithThenFetchMany()
+		{
+			Person dbPerson;
+			Person cachePerson;
+			using (var session = OpenSession())
+			using (var transaction = session.BeginTransaction())
+			{
+				var query =
+					session
+						.Query<Person>()
+						.FetchMany(p => p.Children)
+							.ThenFetchMany(ch => ch.Pets)
+						.FetchMany(p => p.Cars) as IQueryable<Person>;
+
+				query = query.WithOptions(opt =>
+					opt.SetCacheable(true)
+						.SetCacheMode(CacheMode.Normal)
+						.SetCacheRegion("Long_Cache"));
+
+				dbPerson = query.ToList().First(); // First time the result will be cached
+				cachePerson = query.ToList().First();
+
+				transaction.Commit();
+			}
+
+			Assert.That(NHibernateUtil.IsInitialized(dbPerson.Cars), Is.True);
+			Assert.That(NHibernateUtil.IsInitialized(cachePerson.Cars), Is.True);
+			Assert.That(dbPerson.Cars, Has.Count.EqualTo(2));
+			Assert.That(cachePerson.Cars, Has.Count.EqualTo(2));
+
+			Assert.That(NHibernateUtil.IsInitialized(dbPerson.Children), Is.True);
+			Assert.That(NHibernateUtil.IsInitialized(cachePerson.Children), Is.True);
+			Assert.That(dbPerson.Children, Has.Count.EqualTo(0));
+			Assert.That(cachePerson.Children, Has.Count.EqualTo(0));
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH2559/Person.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+
+namespace NHibernate.Test.NHSpecificTest.GH2559
+{
+	public class Person
+	{
+		public virtual Guid Id { get; set; }
+		public virtual string Name { get; set; }
+		public virtual int Age { get; set; }
+
+		public virtual ISet<Car> Cars
+		{
+			get => _cars ?? (_cars = new HashSet<Car>());
+			set => _cars = value;
+		}
+		private ISet<Car> _cars;
+
+		public virtual ISet<Child> Children
+		{
+			get => _children ?? (_children = new HashSet<Child>());
+			set => _children = value;
+		}
+		private ISet<Child> _children;
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH2559/Pet.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace NHibernate.Test.NHSpecificTest.GH2559
+{
+	public class Pet
+	{
+		public virtual Guid Id { get; set; }
+		public virtual string Name { get; set; }
+
+		public virtual Child Owner { get; set; }
+	}
+}

src/NHibernate/Async/Type/CollectionType.cs

@@ -104,6 +104,11 @@ public override async Task<object> DisassembleAsync(object value, ISessionImplem
 		public override async Task BeforeAssembleAsync(object oid, ISessionImplementor session, CancellationToken cancellationToken)
 		{
 			cancellationToken.ThrowIfCancellationRequested();
+			if (oid == null)
+			{
+				return;
+			}
+
 			var queryCacheQueue = session.PersistenceContext.BatchFetchQueue.QueryCacheQueue;
 			if (queryCacheQueue == null)
 			{