NH-3579 - Fix leaking session in DefaultQueryProvider

Author: hazzik

src/NHibernate.Test/Linq/ExpressionSessionLeakTest.cs

@@ -8,7 +8,7 @@ namespace NHibernate.Test.Linq
 {
 	public class ExpressionSessionLeakTest : LinqTestCase
 	{
-		[Test, KnownBug("NH-3579")]
+		[Test]
 		public void SessionGetsCollected()
 		{
 			var reference = DoLinqInSeparateSession();

src/NHibernate/Linq/DefaultQueryProvider.cs

@@ -20,14 +20,17 @@ public class DefaultQueryProvider : INhQueryProvider
 	{
 		private static readonly MethodInfo CreateQueryMethodDefinition = ReflectionHelper.GetMethodDefinition((DefaultQueryProvider p) => p.CreateQuery<object>(null));
 
+		private readonly WeakReference _session;
+
 		public DefaultQueryProvider(ISessionImplementor session)
 		{
-			Session = session;
+			_session = new WeakReference(session, true);
 		}
 
-		protected virtual ISessionImplementor Session { get; private set; }
-
-		#region IQueryProvider Members
+		protected virtual ISessionImplementor Session
+		{
+			get { return _session.Target as ISessionImplementor; }
+		}
 
 		public virtual object Execute(Expression expression)
 		{
@@ -47,16 +50,14 @@ public virtual IQueryable CreateQuery(Expression expression)
 		{
 			MethodInfo m = CreateQueryMethodDefinition.MakeGenericMethod(expression.Type.GetGenericArguments()[0]);
 
-			return (IQueryable) m.Invoke(this, new[] {expression});
+			return (IQueryable) m.Invoke(this, new object[] {expression});
 		}
 
 		public virtual IQueryable<T> CreateQuery<T>(Expression expression)
 		{
 			return new NhQueryable<T>(this, expression);
 		}
 
-		#endregion
-
 		public virtual object ExecuteFuture(Expression expression)
 		{
 			IQuery query;
@@ -92,7 +93,6 @@ protected virtual object ExecuteFutureQuery(NhLinqExpression nhLinqExpression, I
 
 			object result = method.Invoke(query, new object[0]);
 
-
 			if (nhQuery.ExpressionToHqlTranslationResults.PostExecuteTransformer != null)
 			{
 				((IDelayedValue) result).ExecuteOnEval = nhQuery.ExpressionToHqlTranslationResults.PostExecuteTransformer;