NH-3961 - Linq auto-parameterization failures

doc/reference/modules/query_linq.xml

@@ -8,13 +8,13 @@
   <para>
     The Linq provider works as an extension of the <literal>ISession</literal>. It is defined in the
     <literal>NHibernate.Linq</literal> namespace, so this namespace has to be imported for using the
-    Linq provider. Of course, the LINQ namespace is still needed too.
+    Linq provider. Of course, the Linq namespace is still needed too.
   </para>
   <programlisting><![CDATA[using System.Linq;
 using NHibernate.Linq;]]></programlisting>
   <para>
     Note: NHibernate has another querying API which uses lambda, <link linkend="queryqueryover">QueryOver</link>.
-    It should not be confused with a LINQ provider.
+    It should not be confused with a Linq provider.
   </para>
 
   <sect1 id="querylinq-querystructure">
@@ -545,9 +545,10 @@ IList<Cat> cats =
     }
 }]]></programlisting>
       <para>
-        It is required that at least one of the parameters of the method call has its value originating
-        from an entity. Otherwise, the Linq provider will try to evaluate the method call with .Net
-        runtime.
+        The method call will always be translated to SQL if at least one of the parameters of the
+        method call has its value originating from an entity. Otherwise, the Linq provider will try to
+        evaluate the method call with .Net runtime instead. Since NHibernate 5.0, if this runtime
+        evaluation fails (throws an exception), then the method call will be translated to SQL too.
       </para>
     </sect2>
 
@@ -565,7 +566,7 @@ IList<Cat> cats =
       <para>&nbsp;</para>
       <para>
         As an example, here is how to add support for an <literal>AsNullable</literal> method which
-        would allow to call aggregates which lay yield <literal>null</literal> without to explicitly
+        would allow to call aggregates which may yield <literal>null</literal> without to explicitly
         cast to the nullable type of the aggregate.
       </para>
       <programlisting><![CDATA[public static class NullableExtensions
@@ -579,7 +580,7 @@ IList<Cat> cats =
     }
 }]]></programlisting>
       <para>
-        Adding support in Linq to NHibernate for this custom method requires a generator. For this 
+        Adding support in Linq to NHibernate for a custom method requires a generator. For this
         <literal>AsNullable</literal> method, we need a method generator, declaring statically its
         supported method.
       </para>
@@ -612,8 +613,8 @@ IList<Cat> cats =
       </para>
       <para>
         For adding <literal>AsNullableGenerator</literal> in Linq to NHibernate provider, a new
-        generators registry should be used. Derive from the default one and merge it. (Static
-        declaration of method support case.)
+        generators registry should be used. Derive from the default one and merge it. (Here we
+        have a static declaration of method support case.)
       </para>
       <programlisting><![CDATA[public class ExtendedLinqToHqlGeneratorsRegistry :
 DefaultLinqToHqlGeneratorsRegistry

src/NHibernate.Test/NHSpecificTest/NH3386/Entity.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace NHibernate.Test.NHSpecificTest.NH3386
+{
+	class Entity
+	{
+		public virtual Guid Id { get; set; }
+		public virtual string Name { get; set; }
+	}
+}

src/NHibernate.Test/NHSpecificTest/NH3386/Fixture.cs

@@ -0,0 +1,80 @@
+using System.Linq;
+using NHibernate.Linq;
+using NUnit.Framework;
+using System;
+using NHibernate.SqlCommand;
+
+namespace NHibernate.Test.NHSpecificTest.NH3386
+{
+	[TestFixture]
+	public class Fixture : BugTestCase
+	{
+		protected override bool AppliesTo(Dialect.Dialect dialect)
+		{
+			return dialect is Dialect.MsSql2000Dialect;
+		}
+
+		protected override void OnSetUp()
+		{
+			using (ISession session = OpenSession())
+			using (ITransaction transaction = session.BeginTransaction())
+			{
+				var e1 = new Entity {Name = "Bob"};
+				session.Save(e1);
+
+				var e2 = new Entity {Name = "Sally"};
+				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 ShouldSupportNonRuntimeExtensionWithoutEntityReference()
+		{
+			var sqlInterceptor = new SqlInterceptor();
+			using (ISession session = OpenSession(sqlInterceptor))
+			using (session.BeginTransaction())
+			{
+				var result = session.Query<Entity>()
+					.OrderBy(e => SqlServerFunction.NewID());
+
+				Assert.DoesNotThrow(() => { result.ToList(); });
+				Assert.That(sqlInterceptor.Sql.ToString(), Does.Contain(nameof(SqlServerFunction.NewID)).IgnoreCase);
+			}
+		}
+	}
+
+	public static class SqlServerFunction
+	{
+		[LinqExtensionMethod]
+		public static Guid NewID()
+		{
+			throw new InvalidOperationException("To be translated to SQL only");
+		}
+	}
+
+	public class SqlInterceptor: EmptyInterceptor
+	{
+		public SqlString Sql { get; private set; }
+
+		public override SqlString OnPrepareStatement(SqlString sql)
+		{
+			Sql = sql;
+			return base.OnPrepareStatement(sql);
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/NH3386/Mappings.hbm.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernate.Test" namespace="NHibernate.Test.NHSpecificTest.NH3386">
+
+	<class name="Entity">
+		<id name="Id" generator="guid.comb" />
+		<property name="Name" />
+	</class>
+
+</hibernate-mapping>