Update IIsEntityDecider to use ExpressionsHelper.TryGetMappedType

Author: maca88

src/NHibernate/Linq/ReWriters/AddJoinsReWriter.cs

@@ -1,17 +1,18 @@
 using System;
 using System.Linq;
+using System.Linq.Expressions;
 using NHibernate.Engine;
 using NHibernate.Linq.Clauses;
 using NHibernate.Linq.Visitors;
+using NHibernate.Util;
 using Remotion.Linq;
 using Remotion.Linq.Clauses;
 
 namespace NHibernate.Linq.ReWriters
 {
 	internal interface IIsEntityDecider
 	{
-		bool IsEntity(System.Type type);
-		bool IsIdentifier(System.Type type, string propertyName);
+		bool IsEntity(MemberExpression expression, out bool isIdentifier);
 	}
 
 	public class AddJoinsReWriter : NhQueryModelVisitorBase, IIsEntityDecider
@@ -24,8 +25,8 @@ private AddJoinsReWriter(ISessionFactoryImplementor sessionFactory, QueryModel q
 		{
 			_sessionFactory = sessionFactory;
 			var joiner = new Joiner(queryModel);
-			_memberExpressionJoinDetector = new MemberExpressionJoinDetector(this, joiner);
-			_whereJoinDetector = new WhereJoinDetector(this, joiner);
+			_memberExpressionJoinDetector = new MemberExpressionJoinDetector(this, joiner, _sessionFactory);
+			_whereJoinDetector = new WhereJoinDetector(this, joiner, _sessionFactory);
 		}
 
 		public static void ReWrite(QueryModel queryModel, VisitorParameters parameters)
@@ -59,15 +60,28 @@ public override void VisitNhHavingClause(NhHavingClause havingClause, QueryModel
 			_whereJoinDetector.Transform(havingClause);
 		}
 
+		// Since v5.3
+		[Obsolete("This method has no usages and will be removed in a future version")]
 		public bool IsEntity(System.Type type)
 		{
 			return _sessionFactory.GetImplementors(type.FullName).Any();
 		}
 
+		// Since v5.3
+		[Obsolete("This method has no usages and will be removed in a future version")]
 		public bool IsIdentifier(System.Type type, string propertyName)
 		{
 			var metadata = _sessionFactory.GetClassMetadata(type);
 			return metadata != null && propertyName.Equals(metadata.IdentifierPropertyName);
 		}
+
+		bool IIsEntityDecider.IsEntity(MemberExpression expression, out bool isIdentifier)
+		{
+			isIdentifier =
+				ExpressionsHelper.TryGetMappedType(_sessionFactory, expression, out var mappedType, out var entityPersister, out _, out var memberPath)
+				&& entityPersister?.IdentifierPropertyName == memberPath;
+
+			return mappedType?.IsEntityType == true;
+		}
 	}
 }

src/NHibernate/Linq/Visitors/MemberExpressionJoinDetector.cs

@@ -1,6 +1,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.Linq.Expressions;
+using NHibernate.Engine;
 using NHibernate.Linq.Expressions;
 using NHibernate.Linq.ReWriters;
 using Remotion.Linq.Clauses;
@@ -18,21 +19,26 @@ internal class MemberExpressionJoinDetector : RelinqExpressionVisitor
 	{
 		private readonly IIsEntityDecider _isEntityDecider;
 		private readonly IJoiner _joiner;
+		private readonly ISessionFactoryImplementor _sessionFactory;
 
 		private bool _requiresJoinForNonIdentifier;
 		private bool _preventJoinsInConditionalTest;
 		private bool _hasIdentifier;
 		private int _memberExpressionDepth;
 
-		public MemberExpressionJoinDetector(IIsEntityDecider isEntityDecider, IJoiner joiner)
+		public MemberExpressionJoinDetector(
+			IIsEntityDecider isEntityDecider,
+			IJoiner joiner,
+			ISessionFactoryImplementor sessionFactory)
 		{
 			_isEntityDecider = isEntityDecider;
 			_joiner = joiner;
+			_sessionFactory = sessionFactory;
 		}
 
 		protected override Expression VisitMember(MemberExpression expression)
 		{
-			var isIdentifier = _isEntityDecider.IsIdentifier(expression.Expression.Type, expression.Member.Name);
+			var isEntity = _isEntityDecider.IsEntity(expression, out var isIdentifier);
 			if (isIdentifier)
 				_hasIdentifier = true;
 			if (!isIdentifier)
@@ -43,7 +49,7 @@ protected override Expression VisitMember(MemberExpression expression)
 			if (!isIdentifier)
 				_memberExpressionDepth--;
 
-			if (_isEntityDecider.IsEntity(expression.Type) &&
+			if (isEntity &&
 				((_requiresJoinForNonIdentifier && !_hasIdentifier) || _memberExpressionDepth > 0) &&
 				_joiner.CanAddJoin(expression))
 			{

src/NHibernate/Linq/Visitors/WhereJoinDetector.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Linq.Expressions;
+using NHibernate.Engine;
 using NHibernate.Linq.Clauses;
 using NHibernate.Linq.ReWriters;
 using Remotion.Linq.Clauses;
@@ -62,6 +63,7 @@ internal class WhereJoinDetector : RelinqExpressionVisitor
 		// TODO: There are a number of types of expressions that we didn't handle here due to time constraints.  For example, the ?: operator could be checked easily.
 		private readonly IIsEntityDecider _isEntityDecider;
 		private readonly IJoiner _joiner;
+		private readonly ISessionFactoryImplementor _sessionFactory;
 
 		private readonly Stack<bool> _handled = new Stack<bool>();
 
@@ -71,10 +73,14 @@ internal class WhereJoinDetector : RelinqExpressionVisitor
 		// The following is used for member expressions traversal.
 		private int _memberExpressionDepth;
 
-		internal WhereJoinDetector(IIsEntityDecider isEntityDecider, IJoiner joiner)
+		internal WhereJoinDetector(
+			IIsEntityDecider isEntityDecider,
+			IJoiner joiner,
+			ISessionFactoryImplementor sessionFactory)
 		{
 			_isEntityDecider = isEntityDecider;
 			_joiner = joiner;
+			_sessionFactory = sessionFactory;
 		}
 
 		public void Transform(IClause whereClause)
@@ -296,8 +302,7 @@ protected override Expression VisitMember(MemberExpression expression)
 			// I'm not sure what processing re-linq does to strange member expressions.
 			// TODO: I suspect this code doesn't add the right joins for the last case.
 
-			var isIdentifier = _isEntityDecider.IsIdentifier(expression.Expression.Type, expression.Member.Name);
-
+			var isEntity = _isEntityDecider.IsEntity(expression, out var isIdentifier);
 			if (!isIdentifier)
 				_memberExpressionDepth++;
 
@@ -307,7 +312,7 @@ protected override Expression VisitMember(MemberExpression expression)
 				_memberExpressionDepth--;
 
 			ExpressionValues values = _values.Pop().Operation(pvs => pvs.MemberAccess(expression.Type));
-			if (_isEntityDecider.IsEntity(expression.Type))
+			if (isEntity)
 			{
 				// Don't add joins for things like a.B == a.C where B and C are entities.
 				// We only need to join B when there's something like a.B.D.