Fix wrong order by with ordered collection fetch in Criteria (#2521)

Fixes #1075

Author: bahusoid

src/NHibernate.Test/Async/Criteria/CriteriaQueryTest.cs

@@ -11,6 +11,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Linq;
 using NHibernate.Dialect;
 using NHibernate.Criterion;
 using NHibernate.Linq;
@@ -2085,6 +2086,64 @@ public async Task RestrictionOnSubclassCollectionAsync()
 			s.Close();
 		}
 
+		//NH-2239 (GH-1075) - Wrong OrderBy in generated SQL
+		[Test]
+		public async Task OrderByAndOrderedCollectionAsync()
+		{
+			var reptile1 = new Reptile { SerialNumber = "9" };
+			var reptile2 = new Reptile { SerialNumber = "8" };
+			var reptile3 = new Reptile { SerialNumber = "7" };
+			var reptile4 = new Reptile { SerialNumber = "6" };
+			var reptile5 = new Reptile { SerialNumber = "5" };
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				await (s.SaveAsync(reptile5));
+				await (s.SaveAsync(reptile1));
+				await (s.SaveAsync(reptile2));
+				await (s.SaveAsync(reptile3));
+				await (s.SaveAsync(reptile4));
+
+				reptile1.AddOffspring(reptile4);
+				reptile1.AddOffspring(reptile2);
+				reptile4.Father = reptile3;
+				reptile2.Father = reptile4;
+				reptile1.Father = reptile5;
+				reptile3.AddOffspring(reptile1);
+
+				await (t.CommitAsync());
+			}
+
+			using(var s = OpenSession())
+			{
+				var list = await (s.CreateCriteria(typeof(Reptile))
+							.Fetch(SelectMode.Fetch, "offspring")
+							.AddOrder(Order.Asc("serialNumber"))
+							.SetResultTransformer(Transformers.DistinctRootEntity)
+							.ListAsync<Reptile>());
+
+				var expectedList = list.OrderBy(x => x.SerialNumber).ToList();
+
+				Assert.That(list.Count, Is.EqualTo(5));
+				CollectionAssert.AreEqual(expectedList, list);
+
+				var mother = expectedList.Last();
+				Assert.That(NHibernateUtil.IsInitialized(mother.Offspring), Is.True);
+
+				var expectedAssociationList = mother.Offspring.OrderBy(r => r.Father.Id).ToList();
+				Assert.That(expectedAssociationList.Count, Is.EqualTo(2));
+				CollectionAssert.AreEqual(expectedAssociationList, mother.Offspring);
+			}
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				await (s.DeleteAsync("from Reptile"));
+				await (t.CommitAsync());
+			}
+		}
+
 		[Test]
 		public async Task ClassPropertyAsync()
 		{

src/NHibernate.Test/Criteria/Animal.cs

@@ -61,9 +61,9 @@ public virtual string SerialNumber
 			set { serialNumber = value; }
 		}
 
-		private bool howHappyIsHe;
+		private string howHappyIsHe;
 
-		public virtual bool HowHappyIsHe
+		public virtual string HowHappyIsHe
 		{
 			get { return howHappyIsHe; }
 			set { howHappyIsHe = value; }
@@ -85,6 +85,8 @@ public virtual void AddOffspring(Animal offspring)
 			{
 				this.Offspring = new HashSet<Animal>();
 			}
+
+			offspring.Mother = this;
 			this.Offspring.Add(offspring);
 		}
 	}

src/NHibernate.Test/Criteria/CriteriaQueryTest.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Linq;
 using NHibernate.Dialect;
 using NHibernate.Criterion;
 using NHibernate.Linq;
@@ -2182,6 +2183,64 @@ public void RestrictionOnSubclassCollection()
 			s.Close();
 		}
 
+		//NH-2239 (GH-1075) - Wrong OrderBy in generated SQL
+		[Test]
+		public void OrderByAndOrderedCollection()
+		{
+			var reptile1 = new Reptile { SerialNumber = "9" };
+			var reptile2 = new Reptile { SerialNumber = "8" };
+			var reptile3 = new Reptile { SerialNumber = "7" };
+			var reptile4 = new Reptile { SerialNumber = "6" };
+			var reptile5 = new Reptile { SerialNumber = "5" };
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				s.Save(reptile5);
+				s.Save(reptile1);
+				s.Save(reptile2);
+				s.Save(reptile3);
+				s.Save(reptile4);
+
+				reptile1.AddOffspring(reptile4);
+				reptile1.AddOffspring(reptile2);
+				reptile4.Father = reptile3;
+				reptile2.Father = reptile4;
+				reptile1.Father = reptile5;
+				reptile3.AddOffspring(reptile1);
+
+				t.Commit();
+			}
+
+			using(var s = OpenSession())
+			{
+				var list = s.CreateCriteria(typeof(Reptile))
+							.Fetch(SelectMode.Fetch, "offspring")
+							.AddOrder(Order.Asc("serialNumber"))
+							.SetResultTransformer(Transformers.DistinctRootEntity)
+							.List<Reptile>();
+
+				var expectedList = list.OrderBy(x => x.SerialNumber).ToList();
+
+				Assert.That(list.Count, Is.EqualTo(5));
+				CollectionAssert.AreEqual(expectedList, list);
+
+				var mother = expectedList.Last();
+				Assert.That(NHibernateUtil.IsInitialized(mother.Offspring), Is.True);
+
+				var expectedAssociationList = mother.Offspring.OrderBy(r => r.Father.Id).ToList();
+				Assert.That(expectedAssociationList.Count, Is.EqualTo(2));
+				CollectionAssert.AreEqual(expectedAssociationList, mother.Offspring);
+			}
+
+			using (var s = OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				s.Delete("from Reptile");
+				t.Commit();
+			}
+		}
+
 		[Test]
 		public void ClassProperty()
 		{

src/NHibernate/Loader/JoinWalker.cs

@@ -818,10 +818,9 @@ protected SqlString MergeOrderings(SqlString ass, SqlString orderBy)
 		{
 			if (ass.Length == 0)
 				return orderBy;
-			else if (orderBy.Length == 0)
+			if (orderBy.Length == 0)
 				return ass;
-			else
-				return ass.Append(StringHelper.CommaSpace, orderBy);
+			return orderBy.Append(StringHelper.CommaSpace, ass);
 		}
 
 		protected SqlString MergeOrderings(string ass, SqlString orderBy) {