NH-3247 - Char value gets 'cached' - fix and test cases

src/NHibernate.Test/NHSpecificTest/NH3247/Entity.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace NHibernate.Test.NHSpecificTest.NH3247
+{
+	class Entity
+	{
+		public virtual Guid Id { get; set; }
+		public virtual string Name { get; set; }
+		public virtual Char Initial { get; set; }
+	}
+}

src/NHibernate.Test/NHSpecificTest/NH3247/Fixture.cs

@@ -0,0 +1,58 @@
+using System.Linq;
+using NHibernate.Linq;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.NH3247
+{
+	[TestFixture]
+	public class Fixture : BugTestCase
+	{
+		protected override void OnSetUp()
+		{
+			using (ISession session = OpenSession())
+			using (ITransaction transaction = session.BeginTransaction())
+			{
+				var e1 = new Entity {Name = "Bob", Initial = 'B' };
+				session.Save(e1);
+
+				var e2 = new Entity {Name = "Sally", Initial = 'S' };
+				session.Save(e2);
+
+				session.Flush();
+				transaction.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			using (ISession session = OpenSession())
+			using (ITransaction transaction = session.BeginTransaction())
+			{
+				session.Delete("from System.Object");
+
+				session.Flush();
+				transaction.Commit();
+			}
+		}
+
+		[Test]
+		public void CharParameterValueShouldNotBeCached()
+		{
+			using (ISession session = OpenSession())
+			using (session.BeginTransaction())
+			{
+				var result = session.Query<Entity>()
+					.Where(e => e.Initial == 'B')
+					.Single();
+
+				Assert.AreEqual('B', result.Initial);
+
+				result = session.Query<Entity>()
+					.Where(e => e.Initial == 'S')
+					.Single();
+
+				Assert.AreEqual('S', result.Initial);
+			}
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/NH3247/Mappings.hbm.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernate.Test" namespace="NHibernate.Test.NHSpecificTest.NH3247">
+
+	<class name="Entity">
+		<id name="Id" generator="guid.comb" />
+		<property name="Name" />
+    <property name="Initial" />
+	</class>
+
+</hibernate-mapping>

src/NHibernate.Test/NHibernate.Test.csproj

@@ -736,6 +736,8 @@
     <Compile Include="NHSpecificTest\EntityWithUserTypeCanHaveLinqGenerators\Fixture.cs" />
     <Compile Include="NHSpecificTest\EntityWithUserTypeCanHaveLinqGenerators\FooExample.cs" />
     <Compile Include="NHSpecificTest\EntityWithUserTypeCanHaveLinqGenerators\IExample.cs" />
+    <Compile Include="NHSpecificTest\NH3247\Entity.cs" />
+    <Compile Include="NHSpecificTest\NH3247\Fixture.cs" />
     <Compile Include="NHSpecificTest\NH3386\Entity.cs" />
     <Compile Include="NHSpecificTest\NH3386\Fixture.cs" />
     <Compile Include="NHSpecificTest\NH3961\Entity.cs" />
@@ -3215,6 +3217,7 @@
     <EmbeddedResource Include="NHSpecificTest\NH1291AnonExample\Mappings.hbm.xml" />
   </ItemGroup>
   <ItemGroup>
+    <EmbeddedResource Include="NHSpecificTest\NH3247\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH3386\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH3961\Mappings.hbm.xml" />
     <EmbeddedResource Include="NHSpecificTest\NH3963\Mappings.hbm.xml" />

src/NHibernate/Linq/NhLinqExpression.cs

@@ -30,11 +30,12 @@ public class NhLinqExpression : IQueryExpression
 
 		public NhLinqExpression(Expression expression, ISessionFactoryImplementor sessionFactory)
 		{
-			_expression = NhPartialEvaluatingExpressionTreeVisitor.EvaluateIndependentSubtrees(expression);
+			_expression = NhRelinqQueryParser.PreTransform(expression);
+
 			// We want logging to be as close as possible to the original expression sent from the
-			// application. But if we log before partial evaluation, the log won't include e.g.
-			// subquery expressions if those are defined by the application in a variable referenced
-			// from the main query.
+			// application. But if we log before partial evaluation done in PreTransform, the log won't
+			// include e.g. subquery expressions if those are defined by the application in a variable
+			// referenced from the main query.
 			LinqLogging.LogExpression("Expression (partially evaluated)", _expression);
 
 			_constantToParameterMap = ExpressionParameterVisitor.Visit(ref _expression, sessionFactory);

src/NHibernate/Linq/NhRelinqQueryParser.cs

@@ -13,24 +13,31 @@
 using Remotion.Linq.Parsing.Structure.IntermediateModel;
 using Remotion.Linq.Parsing.Structure.NodeTypeProviders;
 using Remotion.Linq.Parsing.Structure.ExpressionTreeProcessors;
+using NHibernate.Linq.Visitors;
 
 namespace NHibernate.Linq
 {
 	public static class NhRelinqQueryParser
 	{
 		private static readonly QueryParser QueryParser;
+		private static readonly IExpressionTreeProcessor PreProcessor;
 
 		static NhRelinqQueryParser()
 		{
+			var preTransformerRegistry = new ExpressionTransformerRegistry();
+			// NH-3247: must remove .Net compiler char to int conversion before
+			// parameterization occurs.
+			preTransformerRegistry.Register(new RemoveCharToIntConversion());
+			PreProcessor = new TransformingExpressionTreeProcessor(preTransformerRegistry);
+
 			var transformerRegistry = ExpressionTransformerRegistry.CreateDefault();
-			transformerRegistry.Register(new RemoveCharToIntConversion());
 			transformerRegistry.Register(new RemoveRedundantCast());
 			transformerRegistry.Register(new SimplifyCompareTransformer());
 
 			// If needing a compound processor for adding other processing, do not use
 			// ExpressionTreeParser.CreateDefaultProcessor(transformerRegistry), it would
 			// cause NH-3961 again by including a PartialEvaluatingExpressionTreeProcessor.
-			// Directly instanciate a CompoundExpressionTreeProcessor instead.
+			// Directly instantiate a CompoundExpressionTreeProcessor instead.
 			var processor = new TransformingExpressionTreeProcessor(transformerRegistry);
 
 			var nodeTypeProvider = new NHibernateNodeTypeProvider();
@@ -39,6 +46,18 @@ static NhRelinqQueryParser()
 			QueryParser = new QueryParser(expressionTreeParser);
 		}
 
+		/// <summary>
+		/// Applies the minimal transformations required before parameterization,
+		/// expression key computing and parsing.
+		/// </summary>
+		/// <param name="expression">The expression to transform.</param>
+		/// <returns>The transformed expression.</returns>
+		public static Expression PreTransform(Expression expression)
+		{
+			var partiallyEvaluatedExpression = NhPartialEvaluatingExpressionTreeVisitor.EvaluateIndependentSubtrees(expression);
+			return PreProcessor.Process(partiallyEvaluatedExpression);
+		}
+
 		public static QueryModel Parse(Expression expression)
 		{
 			return QueryParser.GetParsedQuery(expression);