Merge pull request #403 from hazzik/NH-2738

NH-2738 - Fix getting default Enum value in AbstractEnumType

Author: hazzik

src/NHibernate.Test/MappingByCode/IntegrationTests/NH2738/Fixture.cs

@@ -1,34 +1,49 @@
+using System;
 using NHibernate.Mapping.ByCode;
 using NUnit.Framework;
 
 namespace NHibernate.Test.MappingByCode.IntegrationTests.NH2738
 {
 	public enum MyEmptyEnum
 	{
-		
+	}
+
+	public enum WierdEnum
+	{
+		MinusOne = -1,
+		Zero = 0,
+		PlusOne = 1
 	}
 
 	public class MyClass
 	{
 		public virtual int Id { get; set; }
-		public MyEmptyEnum MyEmptyEnum { get; set; }
+		public virtual MyEmptyEnum MyEmptyEnum { get; set; }
 	}
+
 	public class Fixture
 	{
 		[Test]
-		public void WhenMapEmptyEnumThenThrowsExplicitException()
+		public void WhenMapEmptyEnumThenDoesNotThrowExplicitException()
 		{
 			var mapper = new ModelMapper();
 			mapper.Class<MyClass>(rc =>
-								  {
-															rc.Id(x => x.Id);
-															rc.Property(x => x.MyEmptyEnum);
-								  });
+			{
+				rc.Id(x => x.Id);
+				rc.Property(x => x.MyEmptyEnum);
+			});
 			var mappings = mapper.CompileMappingForAllExplicitlyAddedEntities();
 			var conf = TestConfigurationHelper.GetDefaultConfiguration();
 			conf.AddMapping(mappings);
+			Assert.That(() => conf.BuildSessionFactory(), Throws.Nothing);
+		}
 
-			Assert.That(() => conf.BuildSessionFactory(), Throws.TypeOf<MappingException>().And.Message.ContainsSubstring("MyEmptyEnum"));
+		[Test]
+		public void DefaultOfWierdEnumIsZero()
+		{
+			Assert.That(Activator.CreateInstance(typeof (WierdEnum)), Is.EqualTo(WierdEnum.Zero));
+			Assert.That(Enum.ToObject(typeof (WierdEnum), 0), Is.EqualTo(WierdEnum.Zero));
+			Assert.That(Enum.GetValues(typeof (WierdEnum)).GetValue(0), Is.EqualTo(WierdEnum.Zero)); // This depends on implementation and can be wrong
 		}
 	}
 }

src/NHibernate/Type/AbstractEnumType.cs

@@ -24,7 +24,7 @@ protected AbstractEnumType(SqlType sqlType,System.Type enumType)
 			{
 				throw new MappingException(enumType.Name + " did not inherit from System.Enum");
 			}
-			defaultValue = Enum.GetValues(enumType).GetValue(0);
+			defaultValue = Enum.ToObject(enumType, 0);
 		}
 
 		private readonly object defaultValue;

src/NHibernate/Type/TypeFactory.cs

@@ -520,14 +520,7 @@ public static IType HeuristicType(string typeName, IDictionary<string, string> p
 			var unwrapped = typeClass.UnwrapIfNullable();
 			if (unwrapped.IsEnum)
 			{
-				try
-				{
-					return (IType) Activator.CreateInstance(typeof (EnumType<>).MakeGenericType(unwrapped));
-				}
-				catch (Exception e)
-				{
-					throw new MappingException(string.Format("Can't instantiate enum {0}; The enum can't be empty", typeClass.FullName), e);
-				}
+				return (IType) Activator.CreateInstance(typeof (EnumType<>).MakeGenericType(unwrapped));
 			}
 
 			if (!typeClass.IsSerializable)