Merge pull request nhibernate#71 from hazzik/NH-3044

NH 3044: Linq Self-joined query with subquery and order by - order by didn't apply the outer query

Author: oskarb

src/NHibernate.Test/Linq/ByMethod/OrderByTests.cs

@@ -153,5 +153,29 @@ public void OrderByDoesNotFilterResultsOnJoin()
 			// We to ToList() first or it skips the generation of the joins.
 			Assert.AreEqual(allAnimals.ToList().Count(), orderedAnimals.ToList().Count());
 		}
+		
+		[Test]
+		public void OrderByWithSelfReferencedSubquery1()
+		{
+			//NH-3044
+			var result = (from order in db.Orders
+						  where order == db.Orders.OrderByDescending(x => x.OrderDate).First(x => x.Customer == order.Customer)
+						  orderby order.Customer.CustomerId 
+						  select order).ToList();
+
+			AssertOrderedBy.Ascending(result.Take(5).ToList(), x => x.Customer.CustomerId);
+		}
+		
+		[Test]
+		public void OrderByWithSelfReferencedSubquery2()
+		{
+			//NH-3044
+			var result = (from order in db.Orders
+						  where order == db.Orders.OrderByDescending(x => x.OrderDate).First(x => x.Customer == order.Customer)
+						  orderby order.ShippingDate descending 
+						  select order).ToList();
+
+			AssertOrderedBy.Descending(result.Take(5).ToList(), x => x.ShippingDate);
+		}
 	}
 }

src/NHibernate/Linq/IntermediateHqlTree.cs

@@ -121,7 +121,7 @@ private void ExecuteAddOrderBy(HqlTreeNode orderBy)
 			if (orderBy == null)
 				return;
 
-			if (!_root.NodesPreOrder.OfType<HqlOrderBy>().Any())
+			if (!_root.NodesPreOrder.Any(x => x == orderBy))
 				_root.As<HqlQuery>().AddChild(orderBy);
 		}