NH-3488 - Protect against invalid use cases.

Author: fredericDelaporte

src/NHibernate.Test/LinqBulkManipulation/Fixture.cs

@@ -877,6 +877,19 @@ public void UpdateSetNullOnJoinedSubclass()
 			}
 		}
 
+		[Test]
+		public void UpdateOnOtherClassThrows()
+		{
+			using (var s = OpenSession())
+			using (s.BeginTransaction())
+			{
+				var query = s
+					.Query<Animal>().Where(x => x.Mother == _butterfly)
+					.Update();
+				Assert.That(() => query.As(a => new Human { Description = a.Description + " humanized" }), Throws.TypeOf<TypeMismatchException>());
+			}
+		}
+
 		#endregion
 
 		#region DELETES
@@ -1102,6 +1115,19 @@ public void DeleteSyntaxWithCompositeId()
 			}
 		}
 
+		[Test]
+		public void DeleteOnProjectionThrows()
+		{
+			using (var s = OpenSession())
+			using (s.BeginTransaction())
+			{
+				var query = s
+					.Query<Animal>().Where(x => x.Mother == _butterfly)
+					.Select(x => new Car { Id = x.Id });
+				Assert.That(() => query.Delete(), Throws.InvalidOperationException);
+			}
+		}
+
 		#endregion
 	}
 }

src/NHibernate/Linq/DmlExpressionRewriter.cs

@@ -107,6 +107,8 @@ public static Expression PrepareExpression<TSource>(Expression sourceExpression,
 
 		static Dictionary<string, Expression> ExtractAssignments<TSource, TTarget>(Expression<Func<TSource, TTarget>> expression, MemberInitExpression memberInitExpression)
 		{
+			if (memberInitExpression.Type != typeof(TTarget))
+				throw new TypeMismatchException($"Expecting an expression of exact type {typeof(TTarget).AssemblyQualifiedName} but got {memberInitExpression.Type.AssemblyQualifiedName}");
 			var instance = new DmlExpressionRewriter(expression.Parameters);
 			instance.AddSettersFromBindings(memberInitExpression.Bindings, "");
 			return instance._assignments;

src/NHibernate/Linq/Visitors/QueryModelVisitor.cs

@@ -378,6 +378,7 @@ public override void VisitSelectClause(SelectClause selectClause, QueryModel que
 			switch (_queryMode)
 			{
 				case QueryMode.Delete:
+					VisitDeleteClause(selectClause.Selector);
 					return;
 				case QueryMode.Update:
 				case QueryMode.UpdateVersioned:
@@ -448,6 +449,18 @@ private void VisitUpdateClause(Expression expression)
 			}
 		}
 
+		private void VisitDeleteClause(Expression expression)
+		{
+			// We only need to check there is no unexpected select, for avoiding silently ignoring them.
+			var visitor = new SelectClauseVisitor(typeof(object[]), VisitorParameters);
+			visitor.VisitSelector(expression);
+
+			if (visitor.ProjectionExpression != null)
+			{
+				throw new InvalidOperationException("Delete is not allowed on projections.");
+			}
+		}
+
 		public override void VisitWhereClause(WhereClause whereClause, QueryModel queryModel, int index)
 		{
 			var visitor = new SimplifyConditionalVisitor();