Fix property type retrieval for Composite User Type in LINQ

src/NHibernate.Test/Async/NHSpecificTest/GH2856/Fixture.cs

@@ -0,0 +1,55 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by AsyncGenerator.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+
+using System.Linq;
+using NUnit.Framework;
+using NHibernate.Linq;
+
+namespace NHibernate.Test.NHSpecificTest.GH2856
+{
+	using System.Threading.Tasks;
+	[TestFixture]
+	public class FixtureAsync : BugTestCase
+	{
+		protected override void OnSetUp()
+		{
+			using (var s = Sfi.OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				s.Save(new Entity {Name = "Company", Phone = new PhoneNumber("745-555-1234"),});
+				s.Save(new Entity {Name = "Bob", Phone = new PhoneNumber("745-555-1234", "x123"),});
+				s.Save(new Entity {Name = "Jane", Phone = new PhoneNumber("745-555-1235"),});
+				s.Flush();
+				t.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var s = Sfi.OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				s.Delete("from Entity");
+				s.Flush();
+				t.Commit();
+			}
+		}
+
+		[Test]
+		public async Task CanDistinctOnCompositeUserTypeAsync()
+		{
+			using (var s = OpenSession())
+			{
+				var numbers = await (s.Query<Entity>().Select(x => x.Phone.Ext).Distinct().ToListAsync());
+				Assert.That(numbers.Count, Is.EqualTo(2));
+			}
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH2856/Entity.cs

@@ -0,0 +1,9 @@
+namespace NHibernate.Test.NHSpecificTest.GH2856
+{
+	public class Entity
+	{
+		public int? Id { get; set; }
+		public string Name { get; set; }
+		public PhoneNumber Phone { get; set; }
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH2856/Fixture.cs

@@ -0,0 +1,43 @@
+using System.Linq;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.GH2856
+{
+	[TestFixture]
+	public class Fixture : BugTestCase
+	{
+		protected override void OnSetUp()
+		{
+			using (var s = Sfi.OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				s.Save(new Entity {Name = "Company", Phone = new PhoneNumber("745-555-1234"),});
+				s.Save(new Entity {Name = "Bob", Phone = new PhoneNumber("745-555-1234", "x123"),});
+				s.Save(new Entity {Name = "Jane", Phone = new PhoneNumber("745-555-1235"),});
+				s.Flush();
+				t.Commit();
+			}
+		}
+
+		protected override void OnTearDown()
+		{
+			using (var s = Sfi.OpenSession())
+			using (var t = s.BeginTransaction())
+			{
+				s.Delete("from Entity");
+				s.Flush();
+				t.Commit();
+			}
+		}
+
+		[Test]
+		public void CanDistinctOnCompositeUserType()
+		{
+			using (var s = OpenSession())
+			{
+				var numbers = s.Query<Entity>().Select(x => x.Phone.Ext).Distinct().ToList();
+				Assert.That(numbers.Count, Is.EqualTo(2));
+			}
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH2856/Mappings.hbm.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernate.Test" namespace="NHibernate.Test.NHSpecificTest.GH2856">
+  <class name="Entity" table="a" lazy="false" optimistic-lock="dirty" dynamic-update="true">
+    <id name="Id" column="id" unsaved-value="null">
+      <generator class="native" />
+    </id>
+    <property name="Name"/>
+    <property name="Phone" type="NHibernate.Test.NHSpecificTest.GH2856.PhoneNumberUserType, NHibernate.Test">
+      <column name="PhoneNumber"/>
+      <column name="PhoneExt"/>
+    </property>
+  </class>
+</hibernate-mapping>

src/NHibernate.Test/NHSpecificTest/GH2856/PhoneNumber.cs

@@ -0,0 +1,15 @@
+namespace NHibernate.Test.NHSpecificTest.GH2856
+{
+	public class PhoneNumber
+	{
+		public PhoneNumber(string number, string ext = null)
+		{
+			Number = number;
+			Ext = ext;
+		}
+
+		public string Number { get; }
+
+		public string Ext { get; }
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH2856/PhoneNumberUserType.cs

@@ -0,0 +1,102 @@
+using System;
+using System.Data.Common;
+using NHibernate.Engine;
+using NHibernate.Type;
+using NHibernate.UserTypes;
+
+namespace NHibernate.Test.NHSpecificTest.GH2856
+{
+	class PhoneNumberUserType : ICompositeUserType
+	{
+		public string[] PropertyNames
+		{
+			get { return new[] {"Number", "Ext"}; }
+		}
+
+		public IType[] PropertyTypes
+		{
+			get { return new IType[] {NHibernateUtil.String, NHibernateUtil.String}; }
+		}
+
+		public object GetPropertyValue(object component, int property)
+		{
+			PhoneNumber phone = (PhoneNumber) component;
+
+			switch (property)
+			{
+				case 0: return phone.Number;
+				case 1: return phone.Ext;
+				default: throw new NotImplementedException();
+			}
+		}
+
+		public void SetPropertyValue(object component, int property, object value)
+		{
+			throw new NotImplementedException();
+		}
+
+		public System.Type ReturnedClass
+		{
+			get { return typeof(PhoneNumber); }
+		}
+
+		public new bool Equals(object x, object y)
+		{
+			if (ReferenceEquals(x, null) && ReferenceEquals(y, null))
+				return true;
+
+			if (ReferenceEquals(x, null) || ReferenceEquals(y, null))
+				return false;
+
+			return x.Equals(y);
+		}
+
+		public int GetHashCode(object x)
+		{
+			return x.GetHashCode();
+		}
+
+		public object NullSafeGet(DbDataReader dr, string[] names, ISessionImplementor session, object owner)
+		{
+			return dr.IsDBNull(dr.GetOrdinal(names[0]))
+				? null
+				: (object) new PhoneNumber(
+					(string) NHibernateUtil.String.NullSafeGet(dr, names[0], session, owner),
+					(string) NHibernateUtil.String.NullSafeGet(dr, names[1], session, owner));
+		}
+
+		public void NullSafeSet(DbCommand cmd, object value, int index, bool[] settable, ISessionImplementor session)
+		{
+			object number = value == null ? null : ((PhoneNumber) value).Number;
+			object ext = value == null ? null : ((PhoneNumber) value).Ext;
+
+			if (settable[0]) NHibernateUtil.String.NullSafeSet(cmd, number, index++, session);
+			if (settable[1]) NHibernateUtil.String.NullSafeSet(cmd, ext, index, session);
+		}
+
+		public object DeepCopy(object value)
+		{
+			return value;
+		}
+
+		public bool IsMutable
+		{
+			get { return false; }
+		}
+
+		public object Disassemble(object value, ISessionImplementor session)
+		{
+			return value;
+		}
+
+		public object Assemble(object cached, ISessionImplementor session, object owner)
+		{
+			return cached;
+		}
+
+		public object Replace(object original, object target, ISessionImplementor session, object owner)
+		{
+			return original;
+		}
+	}
+}

src/NHibernate/Util/ExpressionsHelper.cs

@@ -367,23 +367,14 @@ private static bool TraverseMembers(
 						break;
 					case IAbstractComponentType componentType:
 						currentComponentType = componentType;
-						if (currentEntityPersister == null)
+						currentType = TryGetComponentPropertyType(componentType, member.Path);
+						if (currentEntityPersister != null)
 						{
-							// When persister is not available (q.OneToManyCompositeElement[0].Prop), try to get the type from the component
-							currentType = TryGetComponentPropertyType(componentType, member.Path);
-						}
-						else
-						{
-							// Concatenate the component property path in order to be able to use EntityMetamodel.GetPropertyType to retrieve the type.
-							// As GetPropertyType supports only components, do not concatenate when dealing with collection composite elements or elements.
 							// q.Component.Prop
 							member = new MemberMetadata(
-								$"{memberPath}.{member.Path}",
+								memberPath + "." + member.Path,
 								member.ConvertType,
 								member.HasIndexer);
-
-							// q.Component.Prop
-							currentType = currentEntityPersister.EntityMetamodel.GetPropertyType(member.Path);
 						}
 
 						break;