Fix Automapper not not propagating union-subtree through class hierarchy (#334)

Author: jcpreston26

src/FluentNHibernate.Testing/AutoMapping/TestFixtures.cs

@@ -525,3 +525,26 @@ public enum PublisherType
         Mixed
     }
 }
+
+namespace FluentNHibernate.Automapping.TestFixtures.UnionChain
+{
+    public class BaseUnionType
+    {
+        public int Id { get; set; }
+    }
+
+    public class ChildUnionType : BaseUnionType
+    {
+        public int Value { get; set; }
+    }
+
+    public class GrandChildUnionType : ChildUnionType
+    {
+        public string Name { get; set; }
+    }
+
+    public class GreatGrandChildUnionType : GrandChildUnionType
+    {
+    }
+}
+

src/FluentNHibernate.Testing/AutoMapping/UnionSubclassConventionTests.cs

@@ -1,5 +1,6 @@
 using FluentNHibernate.Automapping;
 using FluentNHibernate.Automapping.TestFixtures.SuperTypes;
+using FluentNHibernate.Automapping.TestFixtures.UnionChain;
 using NUnit.Framework;
 
 namespace FluentNHibernate.Testing.Automapping
@@ -18,5 +19,29 @@ public void DefaultConventionsAreAppliedToUnionSubClasses()
                 .HasAttribute("name", "Parent_id");
             //.Element("class/union-subclass").Exists();
         }
+
+        [Test]
+        public void UnionSubtypePropagatesThroughHierarchy()
+        {
+            new AutoMappingTester<BaseUnionType>(
+                AutoMap.AssemblyOf<BaseUnionType>()
+                    .Where(x => x.Namespace == typeof(BaseUnionType).Namespace)
+                    .Override<BaseUnionType>(m => m.UseUnionSubclassForInheritanceMapping()))
+                .Element("class[@name = '" + typeof(BaseUnionType).AssemblyQualifiedName + "']")
+                .Exists()
+                .Element("class/union-subclass[@name='" + typeof(ChildUnionType).AssemblyQualifiedName + "']")
+                .Exists()
+                .Element("class/union-subclass/joined-subclass")
+                .DoesntExist()
+                .Element("class/union-subclass[@name='" + typeof(ChildUnionType).AssemblyQualifiedName + "']/" +
+                          "union-subclass[@name='" + typeof(GrandChildUnionType).AssemblyQualifiedName + "']")
+                .Exists()
+                .Element("class/union-subclass[@name='" + typeof(ChildUnionType).AssemblyQualifiedName + "']/" +
+                          "union-subclass[@name='" + typeof(GrandChildUnionType).AssemblyQualifiedName + "']/" +
+                          "union-subclass[@name='" + typeof(GreatGrandChildUnionType).AssemblyQualifiedName + "']")
+                .Exists()
+                ;
+        }
+
     }
 }

src/FluentNHibernate/Automapping/AutoMapper.cs

@@ -78,12 +78,17 @@ private void MapInheritanceTree(Type classType, ClassMappingBase mapping, IList<
                 }
 
                 SubclassMapping subclassMapping;
-
+                var tempSubClassMap = mapping as SubclassMapping;
                 if(!tempIsNull && tempMapping.IsUnionSubclass)
                 {
                     subclassMapping = new SubclassMapping(SubclassType.UnionSubclass);
                     subclassMapping.Set(x => x.Type, Layer.Defaults, inheritedClass.Type);
                 }
+                else if (tempSubClassMap != null && tempSubClassMap.SubclassType == SubclassType.UnionSubclass)
+                {
+                    subclassMapping = new SubclassMapping(SubclassType.UnionSubclass);
+                    subclassMapping.Set(x => x.Type, Layer.Defaults, inheritedClass.Type);
+                }
                 else if(!isDiscriminated)
                 {
                     subclassMapping = new SubclassMapping(SubclassType.JoinedSubclass);