Proper from node detection

Author: bahusoid

src/NHibernate/Linq/IntermediateHqlTree.cs

@@ -139,19 +139,13 @@ public void AddSelectClause(HqlTreeNode select)
 
 		public void AddFromLastChildClause(params HqlTreeNode[] nodes)
 		{
-			var fromChild = GetLastFromChildNode();
+			var fromChild = _root.NodesPreOrder.OfType<HqlFrom>().First().Children.Last();
 			foreach (var node in nodes)
 			{
 				fromChild.AddChild(node);
 			}
 		}
 
-		internal HqlTreeNode GetLastFromChildNode() =>
-			_root.NodesPreOrder
-				.First(x => x.AstNode.Type == HqlSqlWalker.FROM)
-				.Children
-				.Last();
-
 		public void AddInsertClause(HqlIdent target, HqlRange columnSpec)
 		{
 			var into = _insertRoot.NodesPreOrder.OfType<HqlInto>().Single();

src/NHibernate/Linq/Visitors/JoinBuilder.cs

@@ -4,7 +4,6 @@
 using Remotion.Linq;
 using Remotion.Linq.Clauses;
 using Remotion.Linq.Clauses.Expressions;
-using Remotion.Linq.Parsing;
 
 namespace NHibernate.Linq.Visitors
 {
@@ -76,23 +75,5 @@ private void AddJoin(QueryModel queryModel, NhJoinClause joinClause)
 		{
 			queryModel.BodyClauses.Add(joinClause);
 		}
-
-		private class QuerySourceExtractor : RelinqExpressionVisitor
-		{
-			private IQuerySource _querySource;
-
-			public static IQuerySource GetQuerySource(Expression expression)
-			{
-				var sourceExtractor = new QuerySourceExtractor();
-				sourceExtractor.Visit(expression);
-				return sourceExtractor._querySource;
-			}
-
-			protected override Expression VisitQuerySourceReference(QuerySourceReferenceExpression expression)
-			{
-				_querySource = expression.ReferencedQuerySource;
-				return base.VisitQuerySourceReference(expression);
-			}
-		}
 	}
 }

src/NHibernate/Linq/Visitors/QuerySourceExtractor.cs

@@ -0,0 +1,25 @@
+using System.Linq.Expressions;
+using Remotion.Linq.Clauses;
+using Remotion.Linq.Clauses.Expressions;
+using Remotion.Linq.Parsing;
+
+namespace NHibernate.Linq.Visitors
+{
+	internal class QuerySourceExtractor : RelinqExpressionVisitor
+	{
+		private IQuerySource _querySource;
+
+		public static IQuerySource GetQuerySource(Expression expression)
+		{
+			var sourceExtractor = new QuerySourceExtractor();
+			sourceExtractor.Visit(expression);
+			return sourceExtractor._querySource;
+		}
+
+		protected override Expression VisitQuerySourceReference(QuerySourceReferenceExpression expression)
+		{
+			_querySource = expression.ReferencedQuerySource;
+			return base.VisitQuerySourceReference(expression);
+		}
+	}
+}

src/NHibernate/Linq/Visitors/ResultOperatorProcessors/ProcessFetch.cs

@@ -4,6 +4,7 @@
 using NHibernate.Hql.Ast.ANTLR;
 using NHibernate.Persister.Entity;
 using NHibernate.Type;
+using Remotion.Linq.Clauses.StreamedData;
 using Remotion.Linq.EagerFetching;
 
 namespace NHibernate.Linq.Visitors.ResultOperatorProcessors
@@ -12,20 +13,32 @@ public class ProcessFetch
 	{
 		public void Process(FetchRequestBase resultOperator, QueryModelVisitor queryModelVisitor, IntermediateHqlTree tree)
 		{
-			var lastFromNode = tree.GetLastFromChildNode();
-			Process(resultOperator, queryModelVisitor, tree, lastFromNode, GetNodeAlias(lastFromNode));
+			var selector = ((StreamedSequenceInfo) queryModelVisitor.PreviousEvaluationType).ItemExpression;
+			var querySource = QuerySourceExtractor.GetQuerySource(selector);
+			var sourceAlias = queryModelVisitor.VisitorParameters.QuerySourceNamer.GetName(querySource);
+			Process(resultOperator, queryModelVisitor, tree, GetFromNodeByAlias(tree, sourceAlias), sourceAlias);
 		}
 
-		private static string GetNodeAlias(HqlTreeNode lastFrom)
+		private static HqlTreeNode GetFromNodeByAlias(IntermediateHqlTree tree, string sourceAlias)
 		{
-			return lastFrom.Children.Select(x => x.AstNode)
+			return tree.Root.NodesPreOrder
+				.First(x => x.AstNode.Type == HqlSqlWalker.FROM).Children
+				.First(x => GetNodeAlias(x) == sourceAlias);
+		}
+
+		private static string GetNodeAlias(HqlTreeNode fromNode)
+		{
+			return fromNode.Children
+				.Select(x => x.AstNode)
 				.First(x => x.Type == HqlSqlWalker.ALIAS)
 				.Text;
 		}
 
+		// Since v5.5
+		[Obsolete("This method is not used and will be removed in a future version.")]
 		public void Process(FetchRequestBase resultOperator, QueryModelVisitor queryModelVisitor, IntermediateHqlTree tree, string sourceAlias)
 		{
-			Process(resultOperator, queryModelVisitor, tree, null, sourceAlias);
+			Process(resultOperator, queryModelVisitor, tree, GetFromNodeByAlias(tree, sourceAlias), sourceAlias);
 		}
 
 		private void Process(
@@ -72,13 +85,12 @@ private void Process(
 						propType = metadata.GetPropertyType(resultOperator.RelationMember.Name);
 					}
 				}
-				
+
 				if (propType != null && !propType.IsAssociationType)
 				{
 					if (currentNode == null)
 					{
-						currentNode = tree.GetLastFromChildNode()
-									?? throw new InvalidOperationException($"Property {resultOperator.RelationMember.Name} cannot be fetched for this type of query.");
+						throw new InvalidOperationException($"Property {resultOperator.RelationMember.Name} cannot be fetched for this type of query.");
 					}
 
 					currentNode.AddChild(tree.TreeBuilder.Fetch());
@@ -89,12 +101,13 @@ private void Process(
 					{
 						if (componentType == null)
 						{
-							componentType = propType as ComponentType;
-							if (componentType == null)
+							if (!propType.IsComponentType)
 							{
 								throw new InvalidOperationException(
 									$"Property {innerFetch.RelationMember.Name} cannot be fetched from a non component type property {resultOperator.RelationMember.Name}.");
 							}
+
+							componentType = (ComponentType) propType;
 						}
 
 						var subTypeIndex = componentType.GetPropertyIndex(innerFetch.RelationMember.Name);