Separate parameter type detection for Linq queries

Author: maca88

src/NHibernate.DomainModel/Northwind/Entities/Animal.cs

@@ -14,6 +14,7 @@ public class Animal
         public virtual string SerialNumber { get; set; }
 		public virtual string FatherSerialNumber => Father?.SerialNumber;
 		public virtual bool HasFather => Father != null;
+		public virtual Animal FatherOrMother => Father ?? Mother;
 	}
 
     public abstract class Reptile : Animal

src/NHibernate.DomainModel/Northwind/Entities/Role.cs

@@ -8,5 +8,6 @@ public class Role
 		public virtual bool IsActive { get; set; }
 		public virtual AnotherEntity Entity { get; set; }
 		public virtual Role ParentRole { get; set; }
+		public virtual User CreatedBy { get; set; } // Not mapped
 	}
 }

src/NHibernate.DomainModel/Northwind/Entities/User.cs

@@ -44,12 +44,18 @@ public class User : IUser, IEntity
 
 		public virtual Role Role { get; set; }
 
-        public virtual FeatureSet Features { get; set; }
+		public virtual User NotMappedUser => this;
+
+		public virtual FeatureSet Features { get; set; }
 
 		public virtual EnumStoredAsString Enum1 { get; set; }
 
+		public virtual EnumStoredAsString? NullableEnum1 { get; set; }
+
 		public virtual EnumStoredAsInt32 Enum2 { get; set; }
 
+		public virtual EnumStoredAsInt32? NullableEnum2 { get; set; }
+
 		public virtual int NotMapped { get; set; }
 
 		public virtual Role NotMappedRole { get; set; }

src/NHibernate.DomainModel/Northwind/Entities/UserComponent.cs

@@ -13,8 +13,6 @@ public class UserComponent2
     {
         public string OtherProperty1 { get; set; }
 
-		public string OtherProperty2 { get; set; }
-
-		public string OtherProperty3 => OtherProperty1;
+		public string OtherProperty2 => OtherProperty1;
     }
 }

src/NHibernate.DomainModel/Northwind/Entities/UserDto.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 
 namespace NHibernate.DomainModel.Northwind.Entities
 {
@@ -9,11 +10,13 @@ public class UserDto
 		public virtual int InvalidLoginAttempts { get; set; }
 		public virtual string RoleName { get; set; }
 		public virtual UserDto2 Dto2 { get; set; }
+		public virtual List<UserDto2> Dto2List { get; set; } = new List<UserDto2>();
 
 		public UserDto(int id, string name)
 		{
 			Id = id;
 			Name = name;
+			Dto2 = new UserDto2();
 		}
 	}
 

src/NHibernate.DomainModel/Northwind/Mappings/User.hbm.xml

@@ -16,8 +16,14 @@
       <column name="Enum1" length="12" />
     </property>
 
+    <property name="NullableEnum1" type="NHibernate.DomainModel.Northwind.Entities.EnumStoredAsStringType, NHibernate.DomainModel"
+              formula="(case when Enum1 = 'Unspecified' then null else Enum1 end)" insert="false" update="false">
+    </property>
+
     <property name="Enum2" not-null="true" />
 
+    <property name="NullableEnum2" formula="(case when Enum2 = 0 then null else Enum2 end)" insert="false" update="false" />
+
     <property name="Features" not-null="true" />
 
     <many-to-one name="Role" class="Role">
@@ -30,7 +36,6 @@
 
       <component name="OtherComponent" class="UserComponent2">
         <property name="OtherProperty1" type="AnsiString" />
-        <property name="OtherProperty2" type="AnsiString" formula="OtherProperty1"/>
       </component>
     </component>
   </class>

src/NHibernate.Test/Async/Linq/ByMethod/AverageTests.cs

@@ -22,32 +22,10 @@ public class AverageTestsAsync : LinqTestCase
 		[Test]
 		public async Task CanGetAverageOfIntegersAsDoubleAsync()
 		{
-			if (Dialect is Oracle8iDialect)
-			{
-				// The point of this test is to verify that LINQ's Average over an
-				// integer columns yields a non-integer result, even on databases
-				// where the corresponding avg() will yield a return type equal to
-				// the input type. This means the LINQ provider must generate HQL
-				// that cast the input to double inside the call to avg(). This works
-				// fine on most databases, but Oracle causes trouble.
-				//
-				// The dialect maps double to "DOUBLE PRECISION" on Oracle, which
-				// on Oracle has larger precision than C#'s double. When such
-				// values are returned, ODP.NET will convert it to .Net decimal, which
-				// has lower precision and thus causes an overflow exception.
-				//
-				// Some argue that this is a flaw in ODP.NET, others have created
-				// local dialects that use e.g. BINARY_DOUBLE instead, which more
-				// closely matches C#'s IEEE 745 double, see e.g. HHH-1961 and
-				// serveral blogs.
-
-				Assert.Ignore("Not supported on Oracle due to casting/overflow issues.");
-			}
-
 			//NH-2429
 			var average = await (db.Products.AverageAsync(x => x.UnitsOnOrder));
 
 			Assert.AreEqual(average, 10.129870d, 0.000001d);
 		}
 	}
-}
+}

src/NHibernate.Test/Async/Linq/EnumTests.cs

@@ -9,6 +9,7 @@
 
 
 using System.Linq;
+using System.Linq.Expressions;
 using NHibernate.DomainModel.Northwind.Entities;
 using NUnit.Framework;
 using NHibernate.Linq;
@@ -64,5 +65,43 @@ public async Task CanQueryOnEnumStoredAsString_Small_1Async()
 
 			Assert.AreEqual(expectedCount, query.Count);
 		}
+
+		[Test]
+		public async Task ConditionalNavigationPropertyAsync()
+		{
+			EnumStoredAsString? type = null;
+			await (db.Users.Where(o => o.Enum1 == EnumStoredAsString.Large).ToListAsync());
+			await (db.Users.Where(o => EnumStoredAsString.Large != o.Enum1).ToListAsync());
+			await (db.Users.Where(o => (o.NullableEnum1 ?? EnumStoredAsString.Large) == EnumStoredAsString.Medium).ToListAsync());
+			await (db.Users.Where(o => ((o.NullableEnum1 ?? type) ?? o.Enum1) == EnumStoredAsString.Medium).ToListAsync());
+
+			await (db.Users.Where(o => (o.NullableEnum1.HasValue ? o.Enum1 : EnumStoredAsString.Unspecified) == EnumStoredAsString.Medium).ToListAsync());
+			await (db.Users.Where(o => (o.Enum1 != EnumStoredAsString.Large 
+				                    ? (o.NullableEnum1.HasValue ? o.Enum1 : EnumStoredAsString.Unspecified)
+									: EnumStoredAsString.Small) == EnumStoredAsString.Medium).ToListAsync());
+
+
+			await (db.Users.Where(o => (o.Enum1 == EnumStoredAsString.Large ? o.Role : o.Role).Name == "test").ToListAsync());
+		}
+
+		[Test]
+		public async Task CanQueryComplexExpressionOnEnumStoredAsStringAsync()
+		{
+			var type = EnumStoredAsString.Unspecified;
+			var query = await ((from user in db.Users
+						where (user.NullableEnum1 == EnumStoredAsString.Large
+								? EnumStoredAsString.Medium
+								: user.NullableEnum1 ?? user.Enum1
+							) == type
+						select new
+						{
+							user,
+							simple = user.Enum1,
+							condition = user.Enum1 == EnumStoredAsString.Large ? EnumStoredAsString.Medium : user.Enum1,
+							coalesce = user.NullableEnum1 ?? EnumStoredAsString.Medium
+						}).ToListAsync());
+
+			Assert.That(query.Count, Is.EqualTo(0));
+		}
 	}
 }