NH-3727 - Unit tests showing bug and bugfix proposition

src/NHibernate.Test/NHSpecificTest/NH3727/Entity.cs

@@ -0,0 +1,7 @@
+namespace NHibernate.Test.NHSpecificTest.NH3727
+{
+	class Entity
+	{
+		public virtual int Id { get; set; }
+	}
+}

src/NHibernate.Test/NHSpecificTest/NH3727/FixtureByCode.cs

@@ -0,0 +1,93 @@
+using System.Collections.Generic;
+using System.Linq;
+using NHibernate.Cfg.MappingSchema;
+using NHibernate.Criterion;
+using NHibernate.Impl;
+using NHibernate.Mapping.ByCode;
+using NHibernate.Transform;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.NH3727
+{
+	public class ByCodeFixture : TestCaseMappingByCode
+	{
+		protected override HbmMapping GetMappings()
+		{
+			var mapper = new ModelMapper();
+			mapper.Class<Entity>(rc =>
+			{
+				rc.Id(x => x.Id);
+			});
+
+			return mapper.CompileMappingForAllExplicitlyAddedEntities();
+		}
+
+		[Test]
+		public void QueryOverWithSubqueryProjectionCanBeExecutedMoreThanOnce()
+		{
+			using (ISession session = OpenSession())
+			using (session.BeginTransaction())
+			{
+				const int parameter1 = 111;
+
+				var countSubquery = QueryOver.Of<Entity>()
+						.Where(x => x.Id == parameter1) //any condition which makes output SQL has parameter
+						.Select(Projections.RowCount())
+						;
+
+				var originalQueryOver = session.QueryOver<Entity>()
+											   .SelectList(l => l
+																	.Select(x => x.Id)
+																	.SelectSubQuery(countSubquery)
+												)
+											   .TransformUsing(Transformers.ToList);
+
+				originalQueryOver.List<object>();
+
+				Assert.DoesNotThrow(() => originalQueryOver.List<object>(), "Second try to execute QueryOver thrown exception.");
+			}
+		}
+
+		[Test]
+		public void ClonedQueryOverExecutionMakesOriginalQueryOverNotWorking()
+		{
+			// Projections are copied by clone operation. 
+			// SubqueryProjection use SubqueryExpression which holds CriteriaQueryTranslator (class SubqueryExpression { private CriteriaQueryTranslator innerQuery; })
+			// So given CriteriaQueryTranslator is used twice. 
+			// Since CriteriaQueryTranslator has CollectedParameters collection, second execution of the Criteria does not fit SqlCommand parameters.
+
+			using (ISession session = OpenSession())
+			using (session.BeginTransaction())
+			{
+				const int parameter1 = 111;
+
+				var countSubquery = QueryOver.Of<Entity>()
+						.Where(x => x.Id == parameter1) //any condition which makes output SQL has parameter
+						.Select(Projections.RowCount())
+						;
+
+				var originalQueryOver = session.QueryOver<Entity>()
+					//.Where(x => x.Id == parameter2)
+											   .SelectList(l => l
+																	.Select(x => x.Id)
+																	.SelectSubQuery(countSubquery)
+												)
+											   .TransformUsing(Transformers.ToList);
+
+				var clonedQueryOver = originalQueryOver.Clone();
+				clonedQueryOver.List<object>();
+
+				Assert.DoesNotThrow(() => originalQueryOver.List<object>(), "Cloned QueryOver execution caused source QueryOver throw exception when executed.");
+			}
+		}
+
+		private static IEnumerable<IProjection> GetProjectionList(IQueryOver<Entity, Entity> clonedQueryOver)
+		{
+			var projectionList = (((CriteriaImpl)clonedQueryOver.RootCriteria).Projection as ProjectionList);
+			for (int i = 0; i < projectionList.Length; i++)
+			{
+				yield return projectionList[i];
+			}
+		}
+	}
+}

src/NHibernate.Test/NHibernate.Test.csproj

@@ -797,6 +797,8 @@
     <Compile Include="NHSpecificTest\NH3202\Fixture.cs" />
     <Compile Include="NHSpecificTest\NH3604\Entity.cs" />
     <Compile Include="NHSpecificTest\NH3604\FixtureByCode.cs" />
+    <Compile Include="NHSpecificTest\NH3727\Entity.cs" />
+    <Compile Include="NHSpecificTest\NH3727\FixtureByCode.cs" />
     <Compile Include="NHSpecificTest\NH646\Domain.cs" />
     <Compile Include="NHSpecificTest\NH646\Fixture.cs" />
     <Compile Include="NHSpecificTest\NH3234\Fixture.cs" />

src/NHibernate/Criterion/SubqueryExpression.cs

@@ -23,7 +23,7 @@ public abstract class SubqueryExpression : AbstractCriterion
 		[NonSerialized] private CriteriaQueryTranslator innerQuery;
 
 		protected SubqueryExpression(String op, String quantifier, DetachedCriteria dc)
-			:this(op, quantifier, dc, true)
+			: this(op, quantifier, dc, true)
 		{
 		}
 
@@ -44,7 +44,7 @@ public IType[] GetTypes()
 
 		public override SqlString ToSqlString(ICriteria criteria, ICriteriaQuery criteriaQuery, IDictionary<string, IFilter> enabledFilters)
 		{
-			InitializeInnerQueryAndParameters(criteriaQuery);
+			InitializeInnerQueryAndParameters(criteriaQuery, true); // Force reinitialization. There can be old instance from earlier Criteria execution or cloned Criteria.
 
 			if (innerQuery.HasProjection == false)
 			{
@@ -88,7 +88,7 @@ public override SqlString ToSqlString(ICriteria criteria, ICriteriaQuery criteri
 			{
 				buf.Add(quantifier).Add(" ");
 			}
-			
+
 			buf.Add("(").Add(sql).Add(")");
 
 			if (quantifier != null && prefixOp == false)
@@ -101,9 +101,9 @@ public override SqlString ToSqlString(ICriteria criteria, ICriteriaQuery criteri
 
 		public override string ToString()
 		{
-			if(prefixOp)
+			if (prefixOp)
 				return string.Format("{0} {1} ({2})", op, quantifier, criteriaImpl);
-			
+
 			return string.Format("{0} ({1}) {2}", op, criteriaImpl, quantifier);
 		}
 
@@ -117,9 +117,9 @@ public override IProjection[] GetProjections()
 			return null;
 		}
 
-		public void InitializeInnerQueryAndParameters(ICriteriaQuery criteriaQuery)
+		public void InitializeInnerQueryAndParameters(ICriteriaQuery criteriaQuery, bool forceReinitialization = false)
 		{
-			if (innerQuery == null)
+			if (innerQuery == null || forceReinitialization)
 			{
 				ISessionFactoryImplementor factory = criteriaQuery.Factory;